Write data, waiting if necessary
public function writeAllowPartialSuccessAsync( string $bytes, ?int $timeout_ns = NULL, ): Awaitable<int>;
A wrapper around
write() that will wait if
write() would throw
It is possible for the write to partially succeed - check the return value and call again if needed.
?int $timeout_ns = NULL
the- number of bytes written, which may be less than the length of input string.