public static byte[] copy(final byte[] payload,final int offset,final int length){
  final byte[] buffer=new byte[length];
  System.arraycopy(payload,offset,buffer,0,length);
  return buffer;
}

public static byte [ ] copy ( final byte [ ] payload , final int offset , final int length ) { final byte [ ] buffer = new byte [ length ] ; System . arraycopy ( payload , offset , buffer , 0 , length ) ; return buffer ; }
restituisce una copia della parte dell ' array specificata .
