private ChannelFuture doWriteUnsplitData(int id, HttpData data, boolean endStream) {
        final ByteBuf buf = toByteBuf(data);
        boolean handled = false;
        try {
            final HttpContent content;
            if (endStream) {
                content = new DefaultLastHttpContent(buf);
            } else {
                content = new DefaultHttpContent(buf);
            }

            final ChannelFuture future = write(id, content, endStream);
            handled = true;
            ch.flush();
            return future;
        } finally {
            if (!handled) {
                buf.release();
            }
        }
    }
The map which maps a request ID to its related pending response.
core/src/main/java/com/linecorp/armeria/internal/common/Http1ObjectEncoder.java