*/
  private transient int @Nullable [] predecessor;

  /**
   * Pointer to the successor of an entry in insertion order. ENDPOINT indicates a node is the last
   * node in insertion order; all values at indices ≥ {@link #size()} are UNSET.
   */
  private transient int @Nullable [] successor;

  /** Pointer to the first node in the linked list, or {@code ENDPOINT} if there are no entries. */

    }
  }

  private static <T extends @Nullable Object> void successor(AvlNode<T> a, AvlNode<T> b) {
    a.succ = b;
    b.pred = a;
  }

  private static <T extends @Nullable Object> void successor(
      AvlNode<T> a, AvlNode<T> b, AvlNode<T> c) {
    successor(a, b);
    successor(b, c);
  }

  /*

    values[size] = value;

    insertIntoTableKToV(size, keyHash);
    insertIntoTableVToK(size, valueHash);

    int successor =
        (predecessor == ENDPOINT) ? firstInInsertionOrder : nextInInsertionOrder[predecessor];
    setSucceeds(predecessor, size);
    setSucceeds(size, successor);
    size++;
    modCount++;
    return null;
  }

  /**

			if ok1 != ok2 {
				t.Errorf("Expected %s, got %s", test.expectedErr, err)
			}
			if test.succmodTimes != nil {
				if !test.expectedSuccModTime.Equal(fi.SuccessorModTime) {
					t.Errorf("Expected successor mod time to be %v but got %v", test.expectedSuccModTime, fi.SuccessorModTime)
				}
				if test.expectedIsLatest != fi.IsLatest {
					t.Errorf("Expected IsLatest to be %v but got %v", test.expectedIsLatest, fi.IsLatest)

	replicationDecision string // internal representation of replication decision for use by DeleteObject handler
	// The total count of all versions of this object
	NumVersions int
	//  The modtime of the successor object version if any
	SuccessorModTime time.Time

	// Checksums added on upload.
	// Encoded, maybe encrypted.
	Checksum []byte

	// Inlined
	Inlined bool

	DataBlocks   int

	}

	// objProps represents properties that go beyond a single version
	type objProps struct {
		succModTime time.Time
		numVersions int
	}
	// Find the successor mod time and numVersions in quorum, otherwise leave the
	// candidate as found
	otherPropsMap := make(counterMap[objProps])
	var candidate FileInfo
	var found bool
	for i, hash := range metaHashes {

Then APIStar stopped to exist as a server and Starlette was created, and was a new better foundation for such a system. That was the final inspiration to build **FastAPI**.

I consider **FastAPI** a "spiritual successor" to APIStar, while improving and increasing the features, typing system, and other parts, based on the learnings from all these previous tools.

///

## Used by **FastAPI** { #used-by-fastapi }

/**
 * A builder of {@link LoadingCache} and {@link Cache} instances.
 *
 * <h2>Prefer <a href="https://github.com/ben-manes/caffeine/wiki">Caffeine</a> over Guava's caching
 * API</h2>
 *
 * <p>The successor to Guava's caching API is <a
 * href="https://github.com/ben-manes/caffeine/wiki">Caffeine</a>. Its API is designed to make it a
 * nearly drop-in replacement. Note that it is not available for Android or GWT/J2CL and that it may

        // Next call should transition to HALF_OPEN
        String result = circuitBreaker.call(() -> "success");
        assertEquals("success", result);
        assertEquals(SimpleCircuitBreaker.State.HALF_OPEN, circuitBreaker.getState());
    }

    @Test
    @DisplayName("Test circuit closes after success threshold in HALF_OPEN")
    void testCircuitClosesAfterSuccessThreshold() throws Exception {

        // First success should transition to HALF_OPEN
        String result = circuitBreaker.executeWithCircuitBreaker(() -> "success 0");
        assertEquals("success 0", result, "Should execute in HALF_OPEN");
        assertEquals(State.HALF_OPEN, circuitBreaker.getState(), "Should be in HALF_OPEN after first success");

        // Need successThreshold (2) consecutive successes to close the circuit