perf: Add into_bytes to Storable to avoid cloning where possible

[hpeebles]

In OpenChat I have just introduced a StableBTreeMap where the values are Vec<u8>.
I saw that when calling map.insert(..) the bytes were being cloned because Storable::to_bytes take a reference to self so for Vec<u8> the response is Cow::Borrowed(self), then when calling into_owned the bytes are cloned.

This PR adds an optional into_bytes method to the Storable trait which by default simply calls into to_bytes.
Implementing into_bytes allows for values to be inserted with cloning the bytes.

The downside is that I've had to add the Sized trait to Storable which is a breaking change and may not be desired.

[hpeebles]

The same idea may apply to ic_stable_structures::vec::Vec where push takes a reference so there will (almost) always be cloning.

Edit: No, it doesn't apply there because the bytes are never converted to a Vec so there is no cloning already.

[dsarlis]

I'm really not sure about the Size requirement. I feel like it might not be worth it. Is there no other way to go around what happens for Vec<u8>? Maybe we introduce some shortcut of the form "if the value to be encoded is a Vec<u8> then skip serialization altogether" since storing the raw bytes should be fine.

[dsarlis]

Also, using Cow to begin with was to avoid unnecessary cloning until the point where you actually need it. So you're saying you don't want to have any cloning at all? Typically (in most Rust libraries I am aware of), during serialization you don't give up ownership, you pass a reference and that means there needs to be some cloning at some point.

[github-actions]

canbench 🏋 (dir: .)

Significant performance change detected! ⚠️

./canbench_results.yml is not up to date ❌
If the performance change is expected, run canbench --persist to save the updated benchmark results.

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Benchmark: btreemap_insert_blob_4_1024
  total:
    instructions: 615.12 M (regressed by 27.21%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 123 pages (no change)

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Benchmark: btreemap_insert_blob_4_1024_v2
  total:
    instructions: 714.38 M (regressed by 24.91%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 92 pages (no change)

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Benchmark: btreemap_insert_blob_8_1024
  total:
    instructions: 738.00 M (regressed by 24.00%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 183 pages (no change)

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Benchmark: btreemap_insert_blob_8_1024_v2
  total:
    instructions: 840.85 M (regressed by 22.21%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 138 pages (no change)

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Benchmark: btreemap_insert_blob_16_1024
  total:
    instructions: 819.03 M (regressed by 20.93%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 215 pages (no change)

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Benchmark: btreemap_insert_blob_16_1024_v2
  total:
    instructions: 929.41 M (regressed by 22.05%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 161 pages (no change)

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Benchmark: btreemap_insert_blob_32_1024
  total:
    instructions: 870.33 M (regressed by 22.15%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 230 pages (no change)

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Benchmark: btreemap_insert_blob_32_1024_v2
  total:
    instructions: 980.76 M (regressed by 22.56%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 173 pages (no change)

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Benchmark: btreemap_insert_blob_64_1024
  total:
    instructions: 1.14 B (regressed by 15.92%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 245 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_blob_64_1024_v2
  total:
    instructions: 1.25 B (regressed by 17.61%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 183 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_blob_128_1024
  total:
    instructions: 1.44 B (regressed by 14.86%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 260 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_blob_128_1024_v2
  total:
    instructions: 1.54 B (regressed by 15.02%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 195 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_blob_256_1024
  total:
    instructions: 2.01 B (regressed by 11.21%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 292 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_blob_256_1024_v2
  total:
    instructions: 2.12 B (regressed by 11.80%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 219 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_blob_512_1024
  total:
    instructions: 3.14 B (regressed by 8.49%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 351 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_blob_512_1024_v2
  total:
    instructions: 3.25 B (regressed by 9.04%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 263 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_blob_1024_4
  total:
    instructions: 4.94 B (regressed by 3.60%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 235 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_blob_1024_4_v2
  total:
    instructions: 5.05 B (regressed by 4.50%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 176 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_blob_1024_8
  total:
    instructions: 5.02 B (regressed by 3.92%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 237 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_blob_1024_8_v2
  total:
    instructions: 5.14 B (regressed by 4.29%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 178 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_blob_1024_16
  total:
    instructions: 5.04 B (regressed by 3.63%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 241 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_blob_1024_16_v2
  total:
    instructions: 5.15 B (regressed by 4.34%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 181 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_blob_1024_32
  total:
    instructions: 5.05 B (regressed by 3.69%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 239 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_blob_1024_32_v2
  total:
    instructions: 5.17 B (regressed by 4.19%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 180 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_blob_1024_64
  total:
    instructions: 5.08 B (regressed by 3.96%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 250 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_blob_1024_64_v2
  total:
    instructions: 5.20 B (regressed by 4.43%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 188 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_blob_1024_128
  total:
    instructions: 5.08 B (regressed by 4.26%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 262 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_blob_1024_128_v2
  total:
    instructions: 5.20 B (regressed by 4.84%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 196 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_blob_1024_256
  total:
    instructions: 5.11 B (regressed by 4.24%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 292 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_blob_1024_256_v2
  total:
    instructions: 5.22 B (regressed by 4.75%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 219 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_blob_1024_512
  total:
    instructions: 5.23 B (regressed by 5.09%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 348 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_blob_1024_512_v2
  total:
    instructions: 5.35 B (regressed by 5.48%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 261 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_u64_u64
  total:
    instructions: 353.71 M (regressed by 5.07%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 7 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_u64_u64_v2
  total:
    instructions: 442.03 M (regressed by 7.17%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 6 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_u64_blob_8
  total:
    instructions: 343.41 M (regressed by 3.72%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 7 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_u64_blob_8_v2
  total:
    instructions: 429.18 M (regressed by 6.27%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 5 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_blob_8_u64
  total:
    instructions: 333.84 M (regressed by 4.30%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 6 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_blob_8_u64_v2
  total:
    instructions: 448.35 M (regressed by 6.23%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 4 pages (no change)

---------------------------------------------------

Benchmark: btreemap_insert_10mib_values
  total:
    instructions: 133.06 M (regressed by 62.23%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 32 pages (no change)

---------------------------------------------------

Benchmark: btreemap_read_keys_from_range
  total:
    instructions: 112.24 M (regressed by 36.08%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_read_every_third_value_from_range
  total:
    instructions: 112.24 M (regressed by 36.08%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_iter_small_values
  total:
    instructions: 13.98 M (regressed by 4.01%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_iter_rev_small_values
  total:
    instructions: 13.98 M (regressed by 4.04%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_iter_10mib_values
  total:
    instructions: 17.05 M (regressed by 49.81%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_iter_rev_10mib_values
  total:
    instructions: 17.05 M (regressed by 49.83%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_keys_small_values
  total:
    instructions: 9.99 M (regressed by 5.70%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_keys_rev_small_values
  total:
    instructions: 10.23 M (regressed by 5.61%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_keys_10mib_values
  total:
    instructions: 482.39 K (regressed by 4.54%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_keys_rev_10mib_values
  total:
    instructions: 484.75 K (regressed by 4.74%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_values_small_values
  total:
    instructions: 15.17 M (regressed by 3.68%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_values_rev_small_values
  total:
    instructions: 15.21 M (regressed by 3.70%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_values_10mib_values
  total:
    instructions: 17.08 M (regressed by 49.71%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_values_rev_10mib_values
  total:
    instructions: 17.08 M (regressed by 49.72%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_iter_count_small_values
  total:
    instructions: 9.85 M (regressed by 5.78%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_iter_count_10mib_values
  total:
    instructions: 492.82 K (regressed by 4.30%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_remove_blob_4_1024
  total:
    instructions: 617.91 M (regressed by 31.54%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_remove_blob_4_1024_v2
  total:
    instructions: 735.89 M (regressed by 28.13%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_remove_blob_8_1024
  total:
    instructions: 816.49 M (regressed by 31.72%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_remove_blob_8_1024_v2
  total:
    instructions: 952.85 M (regressed by 28.56%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_remove_blob_16_1024
  total:
    instructions: 1.02 B (regressed by 29.56%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_remove_blob_16_1024_v2
  total:
    instructions: 1.17 B (regressed by 28.54%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_remove_blob_32_1024
  total:
    instructions: 1.10 B (regressed by 29.04%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_remove_blob_32_1024_v2
  total:
    instructions: 1.25 B (regressed by 28.40%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_remove_blob_64_1024
  total:
    instructions: 1.43 B (regressed by 21.34%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_remove_blob_64_1024_v2
  total:
    instructions: 1.59 B (regressed by 22.16%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_remove_blob_128_1024
  total:
    instructions: 1.78 B (regressed by 18.37%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_remove_blob_128_1024_v2
  total:
    instructions: 1.94 B (regressed by 18.66%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_remove_blob_256_1024
  total:
    instructions: 2.45 B (regressed by 14.21%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_remove_blob_256_1024_v2
  total:
    instructions: 2.61 B (regressed by 14.57%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_remove_blob_512_1024
  total:
    instructions: 3.85 B (regressed by 10.14%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_remove_blob_512_1024_v2
  total:
    instructions: 4.00 B (regressed by 10.87%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_remove_u64_u64
  total:
    instructions: 506.70 M (regressed by 4.87%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_remove_u64_u64_v2
  total:
    instructions: 637.22 M (regressed by 6.60%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_remove_u64_blob_8
  total:
    instructions: 486.03 M (regressed by 3.34%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_remove_u64_blob_8_v2
  total:
    instructions: 606.94 M (regressed by 5.44%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_remove_blob_8_u64
  total:
    instructions: 438.22 M (regressed by 4.36%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_remove_blob_8_u64_v2
  total:
    instructions: 591.33 M (regressed by 5.96%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_get_blob_4_1024
  total:
    instructions: 194.41 M (regressed by 9.20%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_get_blob_4_1024_v2
  total:
    instructions: 289.35 M (regressed by 12.79%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_get_blob_8_1024
  total:
    instructions: 231.57 M (regressed by 10.51%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_get_blob_8_1024_v2
  total:
    instructions: 323.20 M (regressed by 13.02%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_get_blob_16_1024
  total:
    instructions: 304.56 M (regressed by 5.52%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_get_blob_16_1024_v2
  total:
    instructions: 409.39 M (regressed by 14.63%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_get_blob_32_1024
  total:
    instructions: 347.92 M (regressed by 9.08%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_get_blob_32_1024_v2
  total:
    instructions: 452.32 M (regressed by 15.86%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_get_blob_64_1024
  total:
    instructions: 599.85 M (regressed by 5.50%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_get_blob_64_1024_v2
  total:
    instructions: 712.04 M (regressed by 10.91%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_get_blob_128_1024
  total:
    instructions: 868.03 M (regressed by 6.26%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_get_blob_128_1024_v2
  total:
    instructions: 970.75 M (regressed by 8.88%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_get_blob_256_1024
  total:
    instructions: 1.40 B (regressed by 6.09%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_get_blob_256_1024_v2
  total:
    instructions: 1.50 B (regressed by 7.40%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_get_blob_512_1024
  total:
    instructions: 2.45 B (regressed by 5.40%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_get_blob_512_1024_v2
  total:
    instructions: 2.56 B (regressed by 6.47%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_get_u64_u64
  total:
    instructions: 187.41 M (regressed by 6.47%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_get_u64_u64_v2
  total:
    instructions: 279.92 M (regressed by 11.35%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_get_u64_blob_8
  total:
    instructions: 186.15 M (regressed by 6.23%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_get_u64_blob_8_v2
  total:
    instructions: 273.25 M (regressed by 11.72%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_get_blob_8_u64
  total:
    instructions: 204.17 M (regressed by 5.61%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: btreemap_get_blob_8_u64_v2
  total:
    instructions: 311.53 M (regressed by 9.56%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: vec_insert_blob_4
  total:
    instructions: 3.35 M (no change)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: vec_insert_blob_8
  total:
    instructions: 3.38 M (no change)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 1 pages (no change)

---------------------------------------------------

Benchmark: vec_insert_blob_16
  total:
    instructions: 3.44 M (no change)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 2 pages (no change)

---------------------------------------------------

Benchmark: vec_insert_blob_32
  total:
    instructions: 3.56 M (no change)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 5 pages (no change)

---------------------------------------------------

Benchmark: vec_insert_blob_64
  total:
    instructions: 3.80 M (no change)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 9 pages (no change)

---------------------------------------------------

Benchmark: vec_insert_blob_128
  total:
    instructions: 4.27 M (no change)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 19 pages (no change)

---------------------------------------------------

Benchmark: vec_insert_u64
  total:
    instructions: 5.66 M (0.18%) (change within noise threshold)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 1 pages (no change)

---------------------------------------------------

Benchmark: vec_get_blob_4
  total:
    instructions: 5.81 M (regressed by 23.26%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: vec_get_blob_8
  total:
    instructions: 6.95 M (regressed by 27.83%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: vec_get_blob_16
  total:
    instructions: 9.82 M (regressed by 26.19%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: vec_get_blob_32
  total:
    instructions: 10.69 M (regressed by 27.15%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: vec_get_blob_64
  total:
    instructions: 15.51 M (regressed by 21.35%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: vec_get_blob_128
  total:
    instructions: 21.38 M (regressed by 20.28%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: vec_get_u64
  total:
    instructions: 6.22 M (regressed by 18.70%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: memory_manager_baseline
  total:
    instructions: 1.18 B (no change)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 8000 pages (no change)

---------------------------------------------------

Benchmark: memory_manager_overhead
  total:
    instructions: 1.18 B (-0.00%) (change within noise threshold)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 8320 pages (no change)

---------------------------------------------------

Benchmark: memory_manager_grow
  total:
    instructions: 348.68 M (-0.27%) (change within noise threshold)
    heap_increase: 2 pages (no change)
    stable_memory_increase: 32.00 K pages (no change)

---------------------------------------------------

[hpeebles]

Woah I didn't get those canbench regressions when running locally!
Let me have a look at what happened here.

[hpeebles]

I think it's probably not worth merging this.
When I run canbench locally I get this improvement

Benchmark: btreemap_insert_10mib_values
  total:
    instructions: 73.82 M (improved by 9.99%)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 32 pages (no change)

But all other benchmarks remain almost exactly the same.
It only helps the case where the value is already a Vec<u8>, so won't benefit many users.
Maybe if Rust ever has specialization then we can somehow add an override which avoids cloning.
But for now I'll close this PR.

[dsarlis]

FYI, there's this old issue which is also related. Indeed, with generic specializations we could implement impl Storable for Vec<T> in an efficient way, also covering the Vec<u8> case. But we need to wait for that.