code: private void writeBlock() throws IOException {
          if (this.debug) {
              System.err.println("WriteBlock: blkIdx = " + this.currBlkIdx);
          }
  
          if (this.outStream == null) {
              throw new IOException("writing to an input buffer");
          }
  
          this.outStream.write(this.blockBuffer, 0, this.blockSize);
          this.outStream.flush();
  
          this.currRecIdx = 0;
          this.currBlkIdx++;
      }
docs: Write a TarBuffer block to the archive.