code: @SuppressWarnings("ConstantConditions")
      @Beta
      public static int countToken(@Nullable String target, String token) {
          checkArgument(token != null && !token.isEmpty(), "Expected non-empty token, got: '%s'", token);
  
          if (isNullOrEmpty(target)) {
              return 0;
          }
  
          int count = 0;
          int tokenIndex = 0;
          while ((tokenIndex = target.indexOf(token, tokenIndex)) != -1) {
              count++;
              tokenIndex += token.length();
          }
          return count;
      }
docs: Returns the number of times the token appears in the target.
  @param token Token value to be counted.
  @param target Target value to count tokens in.
  @return the number of tokens.