code: public final function trimResults() : Splitter
      {
          $splitter = $this->copy();
          $splitter->omitEmptyStrings = $this->omitEmptyStrings;
          $splitter->trimResults = true;
          return $splitter;
      }
docs: Returns a splitter that behaves equivalently to this splitter, but
  automatically removes leading and trailing whitespace characters
  from each returned substring. For example
  <pre>
  Splitter::on(',')->trimResults()->split(' a, b ,c ')
  </pre>
  returns a Traversable containing ["a", "b", "c"].
  
  @return static