make some dependencies optional with benches feature

mqtt/mqtt-broker/Cargo.toml

@@ -9,6 +9,7 @@ bincode = "1.2"
 bytes = "0.5"
 chrono = "0.4"
 config = { version = "0.10", default-features = false, features = ["json"] }
+criterion = { version = "0.3", optional = true }
 crossbeam-channel = "0.4"
 fail = "0.3"
 flate2 = "1.0"
@@ -18,6 +19,7 @@ humantime = "2.0"
 humantime-serde = "1.0"
 lazy_static = "1.4"
 native-tls = "0.2"
+rand = { version = "0.7", optional = true }
 regex = "1"
 serde = { version = "1.0", features = ["derive", "rc"] }
 thiserror = "1.0"
@@ -34,12 +36,10 @@ mqtt3 = { path = "../mqtt3", features = ["serde1"] }
 [dev-dependencies]
 atty = "0.2"
 bytes = "0.5"
-criterion = "0.3"
 fail = { version = "0.3", features = ["failpoints"] }
 itertools = "0.9"
 matches = "0.1"
 proptest = "0.9"
-rand = "0.7"
 serde_json = "1.0"
 tempfile = "3"
 test-case = "1.0"
@@ -53,6 +53,7 @@ required-features = ["fail/failpoints"]
 [[bench]]
 name = "persist_broker_state"
 harness = false
+required-features = ["tokio/rt-threaded"]
 
 [[bench]]
 name = "dispatch_messages"
@@ -62,6 +63,7 @@ required-features = ["__internal_broker_callbacks", "tokio/rt-threaded"]
 [features]
 default = []
 
+benches = ["rand", "criterion", "__internal_broker_callbacks", "tokio/rt-threaded"]
 # Internal (PRIVATE!) features used to aid testing.
 # Don't rely on these whatsoever. They may disappear at anytime.