std::latch::try_wait
Min standard notice:
Returns true only if the internal counter has reached zero. This function may spuriously return false with very low probability even if the internal counter has reached zero.
# Declarations
bool try_wait() const noexcept;
(since C++20)
# Return value
With very low probability false, otherwise cnt == 0, where cnt is the value of the internal counter.
# Notes
The reason why a spurious result is permitted is to allow implementations to use a memory order more relaxed than std::memory_order_seq_cst.