val bodyDelayNanos = response.bodyDelayNanos
      val trailers = response.trailers
      val body = response.body
      val streamHandler = response.streamHandler
      val outFinished = (
        body == null &&
          response.pushPromises.isEmpty() &&
          streamHandler == null
      )
      val flushHeaders = body == null || bodyDelayNanos != 0L
      require(!outFinished || trailers.size == 0) {