/**
 * Denotes that a bean should be created as a singleton instance.
 * <p>
 * Singleton-scoped beans are instantiated once and reused throughout the entire
 * Maven execution. This scope should be used for stateless services or components
 * that can be safely shared across the entire build process.
 * <p>
 * Example usage:
 * <pre>
 * {@literal @}Singleton
 * public class GlobalConfiguration {
 *     // Implementation
 * }

### Services
- Business logic in `app.service.*`
- Injected into Actions
- Use behavior classes to access OpenSearch

### Helpers
- Cross-cutting utilities in `helper.*`
- Stateless, injected via DI
- Access via `ComponentUtil.getFooHelper()`

## Development Notes

- **Code Style**: Enforced by `mvn formatter:format`
- **License Headers**: Required (Apache 2.0) - use `mvn license:format`

	// StatelessHandlerFn must handle incoming stateless request.
	// A non-nil error value will be returned as RemoteErr(msg) to client.
	StatelessHandlerFn func(ctx context.Context, payload []byte, resp chan<- []byte) *RemoteErr

	// StatelessHandler is handlers for one to many requests,
	// where responses may be dropped.
	// Stateless requests provide no incoming stream and there is no flow control

	// Stateless stream:
	if m.Flags&FlagStateless != 0 {
		// Reject for now, so we can safely add it later.
		if true {
			gridLogIf(ctx, c.queueMsg(m, muxConnectError{Error: "Stateless streams not supported"}))
			return
		}

		var handler *StatelessHandler
		if subID == nil {
			handler = c.handlers.stateless[m.Handler]
		} else {

	cancelFn           context.CancelCauseFunc
	parent             *Connection
	respWait           chan<- Response
	respMu             sync.Mutex
	singleResp         bool
	closed             bool
	stateless          bool
	acked              bool
	init               bool
	deadline           time.Duration
	outBlock           chan struct{}
	subroute           *subHandlerID
	respErr            atomic.Pointer[error]

 * resulting XML document is parsed, the parser API will return this text as the original literal
 * string {@code "Foo<Bar>"}.
 *
 * <p>A {@code CharEscaper} instance is required to be stateless, and safe when used concurrently by
 * multiple threads.
 *
 * <p>Popular escapers are defined as constants in classes like {@link
 * com.google.common.html.HtmlEscapers} and {@link com.google.common.xml.XmlEscapers}. To create

  /**
   * A strategy to translate T instances, to {@code numHashFunctions} bit indexes.
   *
   * <p>Implementations should be collections of pure functions (i.e. stateless).
   */
  interface Strategy extends Serializable {

    /**
     * Sets {@code numHashFunctions} bits of the given bit array, by hashing a user element.
     *

 *   <li><b>pure function:</b> the value produced must depend only on the input bytes, in the order
 *       they appear. Input data is never modified. {@link HashFunction} instances should always be
 *       stateless, and therefore thread-safe.
 *   <li><b>collision-averse:</b> while it can't be helped that a hash function will sometimes
 *       produce the same hash code for distinct inputs (a "collision"), every hash function strives

 *   <li><b>pure function:</b> the value produced must depend only on the input bytes, in the order
 *       they appear. Input data is never modified. {@link HashFunction} instances should always be
 *       stateless, and therefore thread-safe.
 *   <li><b>collision-averse:</b> while it can't be helped that a hash function will sometimes
 *       produce the same hash code for distinct inputs (a "collision"), every hash function strives

 * correctly if you are considering implementing a new escaper you should favor using UnicodeEscaper
 * wherever possible.
 *
 * <p>A {@code UnicodeEscaper} instance is required to be stateless, and safe when used concurrently
 * by multiple threads.
 *
 * <p>Popular escapers are defined as constants in classes like {@link
 * com.google.common.html.HtmlEscapers} and {@link com.google.common.xml.XmlEscapers}. To create