pkg math/rand, type Source64 interface { Int63, Seed, Uint64 }
pkg math/rand, type Source64 interface, Seed(int64)
pkg math/rand, type Source64 interface, Uint64() uint64
pkg net/http, const TrailerPrefix ideal-string
pkg net/http, const TrailerPrefix = "Trailer:"
pkg net/http/httptrace, type ClientTrace struct, TLSHandshakeDone func(tls.ConnectionState, error)
pkg net/http/httptrace, type ClientTrace struct, TLSHandshakeStart func()

		http.NewResponseController(rw).Flush()
	}

	if len(res.Trailer) == announcedTrailers {
		copyHeader(rw.Header(), res.Trailer)
		return
	}

	for k, vv := range res.Trailer {
		k = http.TrailerPrefix + k
		for _, v := range vv {
			rw.Header().Add(k, v)
		}
	}
}

var inOurTests bool // whether we're in our own tests

// shouldPanicOnCopyError reports whether the reverse proxy should