Negotiates a connection through an HTTP server.
        NOTE: This currently only supports HTTP CONNECT-style proxies.

def _negotiate_HTTP(self, dest_addr, dest_port):
        """
        Negotiates a connection through an HTTP server.
        NOTE: This currently only supports HTTP CONNECT-style proxies.
        """
        proxy_type, addr, port, rdns, username, password = self.proxy

        # If we need to resolve locally, we do this now
        addr = dest_addr if rdns else socket.gethostbyname(dest_addr)

        http_headers = [
            b"CONNECT " + addr.encode('idna') + b":" + str(dest_port).encode() + b" HTTP/1.1",
            b"Host: " + dest_addr.encode('idna')
        ]

        if username and password:
            http_headers.append(b"Proxy-Authorization: basic " + b64encode(username + b":" + password))

        http_headers.append(b"\r\n")

        self.sendall(b"\r\n".join(http_headers))

        # We just need the first line to check if the connection was successful
        fobj = self.makefile()
        status_line = fobj.readline()
        fobj.close()

        if not status_line:
            raise GeneralProxyError("Connection closed unexpectedly")

        try:
            proto, status_code, status_msg = status_line.split(" ", 2)
        except ValueError:
            raise GeneralProxyError("HTTP proxy server sent invalid response")

        if not proto.startswith("HTTP/"):
            raise GeneralProxyError("Proxy server does not appear to be an HTTP proxy")

        try:
            status_code = int(status_code)
        except ValueError:
            raise HTTPError("HTTP proxy server did not return a valid HTTP status")

        if status_code != 200:
            error = "{0}: {1}".format(status_code, status_msg)
            if status_code in (400, 403, 405):
                # It's likely that the HTTP proxy server does not support the CONNECT tunneling method
                error += ("\n[*] Note: The HTTP proxy server may not be supported by PySocks"
                          " (must be a CONNECT tunnel proxy)")
            raise HTTPError(error)

        self.proxy_sockname = (b"0.0.0.0", 0)
        self.proxy_peername = addr, dest_port