question: public void writeTo ( byte [ ] bytes , int offset ) throws IOException { flush ( ) ; final long end = file . length ; long pos = 0 ; int buffer = 0 ; int bytesUpto = offset ; while ( pos < end ) { int length = BUFFER_SIZE ; long nextPos = pos + length ; if ( nextPos > end ) { length = ( int ) ( end - pos ) ; } System . arraycopy ( file . getBuffer ( buffer ++ ) , 0 , bytes , bytesUpto , length ) ; bytesUpto += length ; pos = nextPos ; } }
target:  Copy the current contents of this buffer to output byte array 