code: function _sanitize (chunk) {
  
    if (chunk && typeof chunk === 'object' && chunk.toString) {
      chunk = chunk.toString();
    }
    if (typeof chunk === 'string') {
      chunk = chunk.replace(/^[\s\n]*/, '');
      chunk = chunk.replace(/[\s\n]*$/, '');
    }
    return chunk;
  }
docs: After ensuring a chunk is a string, trim any leading or
  trailing whitespace.  If chunk cannot be nicely casted to a string,
  pass it straight through.
  
  @param  {*} chunk
  @return {*}