code: public String trimFrom(CharSequence sequence) {
      int len = sequence.length();
      int first;
      int last;
  
      for (first = 0; first < len; first++) {
        if (!matches(sequence.charAt(first))) {
          break;
        }
      }
      for (last = len - 1; last > first; last--) {
        if (!matches(sequence.charAt(last))) {
          break;
        }
      }
  
      return sequence.subSequence(first, last + 1).toString();
    }
docs: Returns a substring of the input character sequence that omits all matching BMP characters from
  the beginning and from the end of the string. For example:
  
  <pre>{@code
  CharMatcher.anyOf("ab").trimFrom("abacatbab")
  }</pre>
  
  ... returns {@code "cat"}.
  
  <p>Note that:
  
  <pre>{@code
  CharMatcher.inRange('\0', ' ').trimFrom(str)
  }</pre>
  
  ... is equivalent to {@link String#trim()}.