streams: add so_rcvbuf and so_sndbuf socket context options.

[devnexen]

They set SO_RCVBUF and SO_SNDBUF in bytes on TCP and UDP sockets, applied before connect() and listen(). Values outside 1 to INT_MAX throw a ValueError.

[NickSdot]

Suggested change

	} catch (ValueError $e) {
	echo $e::class, ': ', $e->getMessage(), PHP_EOL;
	}
	}
	}
	$context = stream_context_create(['socket' => ['so_rcvbuf' => 0]]);
	try {
	@stream_socket_client("tcp://127.0.0.1:1", $errno, $errstr, 1,
	STREAM_CLIENT_CONNECT, $context);
	} catch (ValueError $e) {
	echo $e::class, ': ', $e->getMessage(), PHP_EOL;
	}
	} catch (Throwable $e) {
	echo $e::class, ': ', $e->getMessage(), "\n";
	}
	}
	}
	$context = stream_context_create(['socket' => ['so_rcvbuf' => 0]]);
	try {
	@stream_socket_client("tcp://127.0.0.1:1", $errno, $errstr, 1,
	STREAM_CLIENT_CONNECT, $context);
	} catch (Throwable $e) {
	echo $e::class, ': ', $e->getMessage(), "\n";
	}