}
	if !quotaCfg.IsValid() {
		if quotaCfg.Type == "fifo" {
			internalLogIf(GlobalContext, errors.New("Detected older 'fifo' quota config, 'fifo' feature is removed and not supported anymore. Please clear your quota configs using 'mc quota clear alias/bucket' and use 'mc ilm add' for expiration of objects"), logger.WarningKind)
			return quotaCfg, fmt.Errorf("invalid quota type 'fifo'")
		}

import org.jspecify.annotations.NullUnmarked;
import org.jspecify.annotations.Nullable;

/**
 * A bounded {@linkplain BlockingQueue blocking queue} backed by an array. This queue orders
 * elements FIFO (first-in-first-out). The head of the queue is that element that has been
 * on the queue the longest time. The tail of the queue is that element that has been on

 * Executor, and sequentially such that no two will ever be running at the same time.
 *
 * <p>Tasks submitted to {@link #execute(Runnable)} are executed in FIFO order.
 *
 * <p>The execution of tasks is done by one thread as long as there are tasks left in the queue.
 * When a task is {@linkplain Thread#interrupt interrupted}, execution of subsequent tasks

 * Executor, and sequentially such that no two will ever be running at the same time.
 *
 * <p>Tasks submitted to {@link #execute(Runnable)} are executed in FIFO order.
 *
 * <p>The execution of tasks is done by one thread as long as there are tasks left in the queue.
 * When a task is {@linkplain Thread#interrupt interrupted}, execution of subsequent tasks

import java.util.Queue;

/**
 * A non-blocking queue which automatically evicts elements from the head of the queue when
 * attempting to add new elements onto the queue and it is full. This queue orders elements FIFO
 * (first-in-first-out). This data structure is logically equivalent to a circular buffer (i.e.,
 * cyclic buffer or ring buffer).
 *

"^file:.*"         → fileSystemClient
"^ftp://.*"        → ftpClient
"^smb://.*"        → smbClient
"^storage://.*"    → storageClient
```

### Services

**UrlQueueService**: URL queue management (FIFO), duplicate detection via `visited()`
**DataService**: Access result persistence, iteration

**Implementations**:
- `UrlQueueServiceImpl`, `DataServiceImpl`: In-memory (default)

    }

    /**
     * Creates and returns a new instance of {@link SynchronousQueue}.
     *
     * @param <E> the element type of {@link SynchronousQueue}
     * @param fair whether the access order is FIFO for waiting threads
     * @return a new instance of {@link SynchronousQueue}
     * @see SynchronousQueue#SynchronousQueue()
     */
    public static <E> SynchronousQueue<E> newSynchronousQueue(final boolean fair) {

type ObjReaderFn func(inputReader io.Reader, h http.Header, cleanupFns ...func()) (r *GetObjectReader, err error)

// NewGetObjectReader creates a new GetObjectReader. The cleanUpFns
// are called on Close() in FIFO order as passed in ObjReadFn(). NOTE: It is
// assumed that clean up functions do not panic (otherwise, they may
// not all run!).
func NewGetObjectReader(rs *HTTPRangeSpec, oi ObjectInfo, opts ObjectOptions, h http.Header) (

- github.com/containerd/continuity: [v0.1.0](https://github.com/containerd/continuity/tree/v0.1.0)
- github.com/containerd/fifo: [v1.0.0](https://github.com/containerd/fifo/tree/v1.0.0)
- github.com/containerd/go-runc: [v1.0.0](https://github.com/containerd/go-runc/tree/v1.0.0)
- github.com/containerd/typeurl: [v1.0.2](https://github.com/containerd/typeurl/tree/v1.0.2)

- github.com/containerd/continuity: [aaeac12](https://github.com/containerd/continuity/tree/aaeac12)
- github.com/containerd/fifo: [a9fb20d](https://github.com/containerd/fifo/tree/a9fb20d)
- github.com/containerd/go-runc: [5a6d9f3](https://github.com/containerd/go-runc/tree/5a6d9f3)
- github.com/containerd/ttrpc: [v1.0.0](https://github.com/containerd/ttrpc/tree/v1.0.0)