Function emit_until_delivered 

pub fn emit_until_delivered(
    emit: impl Fn(),
    delivered: impl Fn() -> bool,
    keep_waiting: impl FnMut() -> bool,
) -> bool

Raise a record with emit until delivered() sees it, re-raising it whenever overflowed counts a loss, for as long as keep_waiting() says to. Returns whether delivered() saw it.

For a caller that must OBSERVE a record it raised — a test asserting on what reached its sink. A record raised while another thread is delivering is held, and one that does not fit is dropped and counted, so in a multi-threaded test binary a record can be lost outright and no amount of waiting or crate::flush delivers it. Measured on nros-node’s lib tests: 8 copies at --test-threads=64 failed 1 run in 48, with 16 records counted lost, the asserted ones among them.

A counted loss may have been a sibling’s record while the caller’s was still held, so a re-raise can deliver the record TWICE: assert on every copy, never on a count. emit must therefore be safe to repeat — a one-shot report (a latch it trips) has to reset its latch inside emit.

keep_waiting is the caller’s budget and back-off, since this crate has no clock: a hosted test passes a deadline that yields, || { std::thread::yield_now(); Instant::now() < deadline }.