Function current_tid 

pub fn current_tid() -> u32

Available on crate feature dial9 and (Android or Linux) only.

OS thread ID (tid) of the calling thread.

gettid() on Linux/Android (a vDSO/syscall); a stable per-thread counter elsewhere. Allocation-free, so it is safe to call from the allocator hook. On hot paths prefer [cached_tid], which pays the syscall once per thread.