def tunnel_request_data(host, port, proxy_auth_header=None):
    r"""
    Return binary content of a CONNECT request.

    >>> from scrapy.utils.python import to_native_str as s
    >>> s(tunnel_request_data("example.com", 8080))
    'CONNECT example.com:8080 HTTP/1.1\r\nHost: example.com:8080\r\n\r\n'
    >>> s(tunnel_request_data("example.com", 8080, b"123"))
    'CONNECT example.com:8080 HTTP/1.1\r\nHost: example.com:8080\r\nProxy-Authorization: 123\r\n\r\n'
    >>> s(tunnel_request_data(b"example.com", "8090"))
    'CONNECT example.com:8090 HTTP/1.1\r\nHost: example.com:8090\r\n\r\n'
    """
    host_value = to_bytes(host, encoding='ascii') + b':' + to_bytes(str(port))
    tunnel_req = b'CONNECT ' + host_value + b' HTTP/1.1\r\n'
    tunnel_req += b'Host: ' + host_value + b'\r\n'
    if proxy_auth_header:
        tunnel_req += b'Proxy-Authorization: ' + proxy_auth_header + b'\r\n'
    tunnel_req += b'\r\n'
    return tunnel_req

    Return binary content of a CONNECT request.

    >>> from scrapy.utils.python import to_native_str as s
    >>> s(tunnel_request_data("example.com", 8080))
    'CONNECT example.com:8080 HTTP/1.1\r\nHost: example.com:8080\r\n\r\n'
    >>> s(tunnel_request_data("example.com", 8080, b"123"))
    'CONNECT example.com:8080 HTTP/1.1\r\nHost: example.com:8080\r\nProxy-Authorization: 123\r\n\r\n'
    >>> s(tunnel_request_data(b"example.com", "8090"))
    'CONNECT example.com:8090 HTTP/1.1\r\nHost: example.com:8090\r\n\r\n'
    
stackoverflow/venv/lib/python3.6/site-packages/scrapy/core/downloader/handlers/http11.py