// effects.
	ErrHijacked = errors.New("http: connection has been hijacked")

	// ErrContentLength is returned by ResponseWriter.Write calls
	// when a Handler set a Content-Length response header with a
	// declared size and then attempted to write more bytes than
	// declared.
	ErrContentLength = errors.New("http: wrote more than the declared Content-Length")

		rc.Flush()
		w.Write(wantBody)
		rc.Flush()
		n, err := io.WriteString(w, "x") // too many
		if err == nil {
			err = rc.Flush()
		}
		// TODO: Check that this is ErrContentLength, not just any error.
		if err == nil {
			t.Errorf("for proto %q, final write = %v, %v; want _, some error", r.Proto, n, err)
		}
	}))

	res, err := cst.c.Get(cst.ts.URL)
	if err != nil {

		rw.Header().Set("Transfer-Encoding", req.FormValue("te"))
		switch {
		case req.FormValue("overwrite") == "1":
			_, err := rw.Write([]byte("foo TOO LONG"))
			if err != ErrContentLength {
				t.Errorf("expected ErrContentLength; got %v", err)
			}
		case req.FormValue("underwrite") == "1":
			rw.Header().Set("Content-Length", "500")
			rw.Write([]byte("too short"))
		default:
			rw.Write([]byte("foo"))

		{"DefaultTransport", Var, 0},
		{"DetectContentType", Func, 0},
		{"Dir", Type, 0},
		{"ErrAbortHandler", Var, 8},
		{"ErrBodyNotAllowed", Var, 0},
		{"ErrBodyReadAfterClose", Var, 0},
		{"ErrContentLength", Var, 0},
		{"ErrHandlerTimeout", Var, 0},
		{"ErrHeaderTooLong", Var, 0},
		{"ErrHijacked", Var, 0},
		{"ErrLineTooLong", Var, 0},
		{"ErrMissingBoundary", Var, 0},

pkg net/http, var DefaultServeMux *ServeMux
pkg net/http, var DefaultTransport RoundTripper
pkg net/http, var ErrBodyNotAllowed error
pkg net/http, var ErrBodyReadAfterClose error
pkg net/http, var ErrContentLength error
pkg net/http, var ErrHandlerTimeout error
pkg net/http, var ErrHeaderTooLong *ProtocolError
pkg net/http, var ErrHijacked error
pkg net/http, var ErrLineTooLong error