Read until we reach
$max_bytes, timeout, or the end of the file
public function readAsync( ?int $max_bytes = NULL, ?float $timeout_seconds = NULL, ): Awaitable<string>;
By default, there is no limit to the size and no timeout, so the entire file will be read; if the handle represents an open pipe, socket, or similar, this means that the call will only return once the connection is closed.
null, there is no limit - this method will read until
end of file, or the timeout is reached.
$max_bytes is 0, the empty string will be returned.
?int $max_bytes = NULL
?float $timeout_seconds = NULL