Defining a subclass of a class defined by the Library is deemed a mode
of using an interface provided by the Library.

  A "Combined Work" is a work produced by combining or linking an
Application with the Library.  The particular version of the Library
with which the Combined Work was made is also called the "Linked
Version".

pkg net/http/httputil, method (*ClientConn) Do(*http.Request) (*http.Response, error)
pkg net/http/httputil, method (*ClientConn) Hijack() (net.Conn, *bufio.Reader)
pkg net/http/httputil, method (*ClientConn) Pending() int
pkg net/http/httputil, method (*ClientConn) Read(*http.Request) (*http.Response, error)
pkg net/http/httputil, method (*ClientConn) Write(*http.Request) error