* and allowing callers to pass arguments that a nullness checker believes could be null.
   *
   * We still encourage people to use requireNonNull over checkNotNull for non-precondition checks.
   */

  /**
   * Ensures that an object reference passed as a parameter to the calling method is not null.
   *
   * @param reference an object reference

     *
     * <p>Canceling this future will attempt to cancel all the component futures.
     *
     * @return a future whose result is based on {@code combiner} (or based on the input futures
     *     passed to {@code whenAllSucceed}, if that is the method you used to create this {@code
     *     FutureCombiner}). Even if you don't care about the value of the future, you should

		if actualErr != nil && testCase.shouldPass {
			t.Errorf("Test %d: %s: Expected to pass, but failed with: <ERROR> %s.", i+1, instanceType, actualErr.Error())
		}
		if actualErr == nil && !testCase.shouldPass {
			t.Errorf("Test %d: %s: Expected to fail with <ERROR> \"%s\", but passed instead.", i+1, instanceType, testCase.expectedError.Error())
		}

//
// Conventions:
// * We use the prefix TF_ for everything in the API.
// * Objects are always passed around as pointers to opaque structs
//   and these structs are allocated/deallocated via the API.
// * TF_Status holds error information.  It is an object type
//   and therefore is passed around as a pointer to an opaque
//   struct as mentioned above.
// * Every call that has a TF_Status* argument clears it on success

// Sign given request using Signature V4.
func signStreamingRequest(req *http.Request, accessKey, secretKey string, currTime time.Time) (string, error) {
	// Get hashed payload.
	hashedPayload := req.Header.Get("x-amz-content-sha256")
	if hashedPayload == "" {
		return "", fmt.Errorf("Invalid hashed payload")
	}

	// Set x-amz-date.
	req.Header.Set("x-amz-date", currTime.Format(iso8601Format))

	// Get header map.

   * the two sets. If you have reason to believe one of your sets will generally be smaller than the
   * other, pass it first. Unfortunately, since this method sets the generic type of the returned
   * set based on the type of the first set passed, this could in rare cases force you to make a
   * cast, for example:
   *
   * {@snippet :
   * Set<Object> aFewBadObjects = ...

			}
			if err != nil && testCase.shouldPass {
				t.Errorf("Test %d: %s:  Expected to pass, but failed with: <ERROR> %s", i+1, instanceType, err.Error())
			}
			if err == nil && !testCase.shouldPass {
				t.Errorf("Test %d: %s: Expected to fail with <ERROR> \"%s\", but passed instead", i+1, instanceType, testCase.err.Error())
			}
			// Failed as expected, but does it fail for the expected reason.

		}, index)
	}

	err := errors.Join(g.Wait()...)
	return policies, err
}

// policyDBGet - lower-level helper; does not take locks.
//
// If a group is passed, it returns policies associated with the group.
//
// If a user is passed, it returns policies of the user along with any groups
// that the server knows the user is a member of.
//
// In LDAP users mode, the server does not store any group membership

    Iterator<String> itr2 = Iterators.concat(itr1, singletonIterator("d"));
    assertEquals("c", itr2.next());
    assertEquals("d", itr2.next());
  }

  /** Illustrates the somewhat bizarre behavior when a null is passed in. */
  public void testConcatContainingNull() {
    Iterator<Iterator<Integer>> input =
        (Iterator<Iterator<Integer>>)
            Arrays.<@Nullable Iterator<Integer>>asList(iterateOver(1, 2), null, iterateOver(3))

    Iterator<String> itr2 = Iterators.concat(itr1, singletonIterator("d"));
    assertEquals("c", itr2.next());
    assertEquals("d", itr2.next());
  }

  /** Illustrates the somewhat bizarre behavior when a null is passed in. */
  public void testConcatContainingNull() {
    Iterator<Iterator<Integer>> input =
        (Iterator<Iterator<Integer>>)
            Arrays.<@Nullable Iterator<Integer>>asList(iterateOver(1, 2), null, iterateOver(3))