docs: public void write(int v) throws IOException {
          final byte[] buffer = this.buffer;
          final int position = this.position;
          if (position == buffer.length) {
              flush();
              buffer[0] = (byte) v;
              this.position = 1;
          } else {
              buffer[position] = (byte) v;
              this.position = position + 1;
          }
      }