code: public static <R> FluentFunctions.FluentSupplier<R> ofChecked(final CheckedSupplier<R> supplier) {
          return FluentFunctions.of(ExceptionSoftener.softenSupplier(supplier));
      }
docs: Construct a FluentSupplier from a checked Supplier
  <pre>
  {@code
  FluentFunctions.ofChecked(this::exceptionalFirstTime)
  .recover(IOException.class, ()->"hello boo!")
  .println()
  .getValue()
  
  }
  </pre>
  @param supplier that throws CheckedExcpetion
  @return FluentSupplier