docs: public synchronized void write(int c) throws IOException {
  
          checkClosed();
  
          int newcount = count + 1;
  
          if (newcount > buf.length) {
              buf = copyOf(buf, Math.max(buf.length << 1, newcount));
          }
  
          buf[count] = (char) c;
          count      = newcount;
      }