docs: public DataSlice getAssembledContent() {
      if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) JmfTr.entry(this, tc, "getAssembledContent");
  
      DataSlice result = null;
  
      // We can only return something useful if the encoding is a JMFMessage.
      if (encoding instanceof JMFMessage) {
  
        // So we just ask the encoding to return what it has (or null)
        result = ((JMFMessage)encoding).getAssembledContent();
      }
  
      if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) JmfTr.exit(this, tc, "getAssembledContent", result);
      return result;
    }