var (
	// verify that an io.Copy from NoBody won't require a buffer:
	_ io.WriterTo   = NoBody
	_ io.ReadCloser = NoBody
)

// PushOptions describes options for [Pusher.Push].
type PushOptions struct {
	// Method specifies the HTTP method for the promised request.
	// If set, it must be "GET" or "HEAD". Empty means "GET".
	Method string

pkg net/http, method (*Server) Shutdown(context.Context) error
pkg net/http, type Pusher interface { Push }
pkg net/http, type Pusher interface, Push(string, *PushOptions) error
pkg net/http, type PushOptions struct
pkg net/http, type PushOptions struct, Header Header
pkg net/http, type PushOptions struct, Method string
pkg net/http, type Request struct, GetBody func() (io.ReadCloser, error)
pkg net/http, type Server struct, IdleTimeout time.Duration

	err         error
	wroteHeader bool
	code        int
}

var _ Pusher = (*timeoutWriter)(nil)

// Push implements the [Pusher] interface.
func (tw *timeoutWriter) Push(target string, opts *PushOptions) error {
	if pusher, ok := tw.w.(Pusher); ok {
		return pusher.Push(target, opts)
	}
	return ErrNotSupported
}

func (tw *timeoutWriter) Header() Header { return tw.h }

		{"PostForm", Func, 0},
		{"ProtocolError", Type, 0},
		{"ProtocolError.ErrorString", Field, 0},
		{"ProxyFromEnvironment", Func, 0},
		{"ProxyURL", Func, 0},
		{"PushOptions", Type, 8},
		{"PushOptions.Header", Field, 8},
		{"PushOptions.Method", Field, 8},
		{"Pusher", Type, 8},
		{"ReadRequest", Func, 0},
		{"ReadResponse", Func, 0},
		{"Redirect", Func, 0},
		{"RedirectHandler", Func, 0},

func (w *http2responseWriter) Push(target string, opts *PushOptions) error {
	st := w.rws.stream
	sc := st.sc
	sc.serveG.checkNotOn()

	// No recursive pushes: "PUSH_PROMISE frames MUST only be sent on a peer-initiated stream."
	// http://tools.ietf.org/html/rfc7540#section-6.6
	if st.isPushed() {
		return http2ErrRecursivePush
	}

	if opts == nil {
		opts = new(PushOptions)
	}

	// Default options.