code: public static Outcome create(final Status status, final URI invocationID,
              @Nullable final URI objectID, @Nullable final String message) {
          return new Outcome(status, invocationID, objectID, message);
      }
docs: Creates a new {@code Outcome} with the status code, invocation ID, optional object ID and
  optional message supplied.
  
  @param status
  the status code, not null
  @param invocationID
  the invocation ID, not null
  @param objectID
  the optional object ID, possibly null
  @param message
  the optional message, possibly null
  @return the created {@code Outcome}