protected final ChannelFuture writeNonInformationalHeaders(
            int id, HttpObject converted, boolean endStream, ChannelPromise promise) {
        ChannelFuture f;
        if (converted instanceof LastHttpContent) {
            assert endStream;
            f = write(id, converted, true, promise);
        } else {
            f = write(id, converted, false, promise);
            if (endStream) {
                final ChannelFuture lastFuture = write(id, LastHttpContent.EMPTY_LAST_CONTENT, true);
                if (Flags.verboseExceptionSampler().isSampled(Http1VerboseWriteException.class)) {
                    f = combine(f, lastFuture);
                } else {
                    f = lastFuture;
                }
            }
        }
        ch.flush();
        return f;
    }
The map which maps a request ID to its related pending response.
core/src/main/java/com/linecorp/armeria/internal/common/Http1ObjectEncoder.java