Consider adding lto = "thin" to generated Cargo.toml's release profile

[itamarst]

In my experience, thin LTO always give a small but noticeable performance boost to PyO3 Python extensions. As such, it would be nice if maturin just added it; one less thing for users to know they have to do.

[profile.release]
lto = "thin"

[konstin]

i haven't been following the upstream discussion, what is the reason that cargo doesn't activate this by default if it gives a noticeable performance boost?

[itamarst]

I assume because of slower compile time.

[konstin]

in that case i would rather align with what cargo is doing; i likely makes sense to ask for that in the cargo repo specifically, the best match i found is rust-lang/cargo#11298