question: protected void removeFromMarkedPosition ( ) { System . arraycopy ( buffer , read_pos , buffer , marked_pos , read_pos_end - read_pos ) ; read_pos_end -= ( read_pos - marked_pos ) ; read_pos = marked_pos ; }
target:  Removes the data from the marked position to the current read position. The method is usefull when it is needed to delete one message from the internal buffer.