
 
        Flushes this output stream and forces any buffered output bytes 
 to be written out. The general contract of 
flush is 
 that calling it is an indication that, if any bytes previously 
 written have been buffered by the implementation of the output 
 stream, such bytes should immediately be written to their 
 intended destination.
 
 If the intended destination of this stream is an abstraction provided by
 the underlying operating system, for example a file, then flushing the
 stream guarantees only that bytes previously written to the stream are
 passed to the operating system for writing; it does not guarantee that
 they are actually written to a physical device such as a disk drive.
 
 The flush method of OutputStream does nothing.
        
        
Throws:
  - IOException - if an I/O error occurs.