public MultiProducerSequencer(int bufferSize,final WaitStrategy waitStrategy){
  super(bufferSize,waitStrategy);
  availableBuffer=new int[bufferSize];
  indexMask=bufferSize - 1;
  indexShift=Util.log2(bufferSize);
  initialiseAvailableBuffer();
}

public MultiProducerSequencer ( int bufferSize , final WaitStrategy waitStrategy ) { super ( bufferSize , waitStrategy ) ; availableBuffer = new int [ bufferSize ] ; indexMask = bufferSize - 1 ; indexShift = Util . log2 ( bufferSize ) ; initialiseAvailableBuffer ( ) ; }
construct a sequencer with the selected wait strategy and buffer size .
