question: @ Override public void write ( String str , int off , int len ) throws IOException { final int off_plus_len = off + len ; for ( int i = off ; i < off_plus_len ; ) { char c = str . charAt ( i ++ ) ; if ( c < 0x80 ) { _bytes [ _index ] = ( byte ) c ; if ( ++ _index >= _bytes . length ) { flushBuffer ( ) ; } } else { write ( c ) ; } } }
target:  Writes a portion of a string.