pub fn reply_id(frame: &[u8]) -> Option<u64>Expand description
If frame is a reply, the id it answers; None for anything else,
including an event and a frame that is not JSON at all.
A reply whose Response this build cannot decode still has a caller
waiting on it. The id is the only thing needed to fail that caller by
name instead of leaving it to wait out its deadline for an answer that
already arrived.