code: public static <T1, T2, R> FluentFunctions.FluentBiFunction<T1, T2, R> ofChecked(final CheckedBiFunction<T1, T2, R> fn) {
          return FluentFunctions.of(ExceptionSoftener.softenBiFunction(fn));
      }
docs: Construct a FluentBiFunction from a CheckedBiFunction
  
  <pre>
  {@code
  FluentFunctions.ofChecked(this::exceptionalFirstTime)
  .println()
  .retry(2,500)
  .applyHKT("hello","woo!")
  }
  </pre>
  @param fn CheckedBiFunction
  @return FluentBiFunction