code: public String trimLeadingFrom(CharSequence sequence) {
      int len = sequence.length();
      for (int first = 0; first < len; first++) {
        if (!matches(sequence.charAt(first))) {
          return sequence.subSequence(first, len).toString();
        }
      }
      return "";
    }
docs: Returns a substring of the input character sequence that omits all matching BMP characters from
  the beginning of the string. For example:
  
  <pre>{@code
  CharMatcher.anyOf("ab").trimLeadingFrom("abacatbab")
  }</pre>
  
  ... returns {@code "catbab"}.