code: public int readLine(Text str, int maxLineLength,
                        int maxBytesToConsume) throws IOException {
      if (this.recordDelimiterBytes != null) {
        return readCustomLine(str, maxLineLength, maxBytesToConsume);
      } else {
        return readDefaultLine(str, maxLineLength, maxBytesToConsume);
      }
    }
docs: Read one line from the InputStream into the given Text.
  
  @param str the object to store the given line (without newline)
  @param maxLineLength the maximum number of bytes to store into str;
  @param maxBytesToConsume the maximum number of bytes to consume
  in this call.  This is only a hint, because if the line cross
  this threshold, we allow it to happen.  It can overshoot
  potentially by as much as one buffer length.