"500": {"description": "Server error level 0"},
                        "501": {"description": "Server error level 1"},
                        "502": {"description": "Server error level 2"},
                        "503": {"description": "Server error level 3"},
                        "504": {"description": "Server error level 4"},
                        "505": {"description": "Server error level 5"},
                    },

pkg net/http, method (Header) Clone() Header
pkg net/http, method (*Request) Clone(context.Context) *Request
pkg net/http, method (*Transport) Clone() *Transport
pkg net/http, type Server struct, BaseContext func(net.Listener) context.Context
pkg net/http, type Server struct, ConnContext func(context.Context, net.Conn) context.Context
pkg net/http, type Transport struct, ForceAttemptHTTP2 bool
pkg net/http, type Transport struct, ReadBufferSize int

If the capacity is zero or absent, the channel is unbuffered and communication
succeeds only when both a sender and receiver are ready. Otherwise, the channel
is buffered and communication succeeds without blocking if the buffer
is not full (sends) or not empty (receives).
A <code>nil</code> channel is never ready for communication.
</p>

<p>
A channel may be closed with the built-in function