Function block_flock 

pub fn block_flock<P: AsRef<Path>>(path: P, mode: FlockMode) -> Result<OwnedFd>

Blocking variant of try_flock. Opens the lockfile (creating it if absent), then issues a blocking flock(2) that parks the caller in the kernel until the lock is available. Use after try_flock returns None to wait for a live peer to finish.