docs: public void resetBuffer() {
          if (com.ibm.ejs.ras.TraceComponent.isAnyTracingEnabled()&&logger.isLoggable (Level.FINE))  //306998.15
              logger.entering(CLASS_NAME,"resetBuffer","["+this+"]");
  
          //is committed check done in underlying layer in tWAS
          if (isCommitted())
              throw new IllegalStateException();
          // LIBERTY
          if (_gotOutputStream)
          {
              _response.resetBuffer();
          }
  
          // LIBERTY if (_responseBuffer != null) {
          // LIBERTY _responseBuffer.clearBuffer();
          // LIBERTY }
  
          // begin 156186
          if (_bufferedWriter != null) {
              _bufferedWriter.clearBuffer();
          }
          // end 156186
          _firstWriteToCurrentBuffer = false;
          if (com.ibm.ejs.ras.TraceComponent.isAnyTracingEnabled()&&logger.isLoggable (Level.FINE))  //306998.15
              logger.exiting(CLASS_NAME,"resetBuffer");
      }