code: public static long readLong(final InputStream inputStream, final byte[] buffer) throws IOException {
          readFully(inputStream, buffer, 8);
          return readLong(buffer);
      }
docs: Reads and returns a single long value from the input stream.
  
  @param inputStream the input stream to read from
  @param buffer the buffer to write the input stream bytes into
  @return the long value
  @throws IOException if there's an error reading from the {@code inputStream}