dap4/d4servlet/src/main/java/dap4/servlet/ChunkWriter.java
@Override
    public void
    flush()
            throws IOException
    {
        if(mode == RequestMode.DMR)
            return; // leave to close() to do this
        if(dmr8 != null) {
            sendDXR(dmr8);
            dmr8 = null;
        }
    }
@Override
    public void
    flush()
            throws IOException
    {
        if(mode == RequestMode.DMR)
            return; // leave to close() to do this
        if(dmr8 != null) {
            sendDXR(dmr8);
            dmr8 = null;
        }
    }
Overload flush to also write out the DMR

@throws IOException