refactor: Avoid accessing prototype in custom_connect

src/custom_connect.ts

@@ -2,15 +2,14 @@ import net from 'net';
 import type http from 'http';
 import { promisify } from 'util';
 
-const asyncWrite = promisify(net.Socket.prototype.write);
-
 export const customConnect = async (socket: net.Socket, server: http.Server): Promise<void> => {
     // `countTargetBytes(socket, socket)` is incorrect here since `socket` is not a target.
     // We would have to create a new stream and pipe traffic through that,
     // however this would also increase CPU usage.
     // Also, counting bytes here is not correct since we don't know how the response is generated
     // (whether any additional sockets are used).
 
+    const asyncWrite = promisify(socket.write).bind(socket);
     await asyncWrite.call(socket, 'HTTP/1.1 200 Connection Established\r\n\r\n');
     server.emit('connection', socket);