code: public static <R> LongFunction<R> longFunction(CheckedLongFunction<R> function) {
          return longFunction(function, THROWABLE_TO_RUNTIME_EXCEPTION);
      }
docs: Wrap a {@link CheckedLongFunction} in a {@link LongFunction}.
  <p>
  Example:
  <code><pre>
  LongStream.of(1L, 2L, 3L).mapToObj(Unchecked.longFunction(l -> {
  if (l &lt; 0L)
  throw new Exception("Only positive numbers allowed");
  
  return "" + l;
  });
  </pre></code>