src/vs/server/node/extensionHostConnection.ts/ExtensionHostConnection/_sendSocketToExtensionHost
class ExtensionHostConnection:	private async _sendSocketToExtensionHost(extensionHostProcess: cp.ChildProcess, connectionData: ConnectionData): Promise<void> {
		// Make sure all outstanding writes have been drained before sending the socket
		await connectionData.socketDrain();
		const msg = connectionData.toIExtHostSocketMessage();
		let socket: net.Socket;
		if (connectionData.socket instanceof NodeSocket) {
			socket = connectionData.socket.socket;
		} else {
			socket = connectionData.socket.socket.socket;
		}
		extensionHostProcess.send(msg, socket);
	}