} else {
        sslSocket.enabledProtocols
      }

    // In accordance with https://tools.ietf.org/html/draft-ietf-tls-downgrade-scsv-00 the SCSV
    // cipher is added to signal that a protocol fallback has taken place.
    val supportedCipherSuites = sslSocket.supportedCipherSuites
    val indexOfFallbackScsv =
      supportedCipherSuites.indexOf(
        "TLS_FALLBACK_SCSV",
        CipherSuite.ORDER_BY_NAME,

    protected void async(final AsyncManager asyncManager, final Runnable runnable) {
        asyncManager.async(new ConcurrentAsyncCall() {
            @Override
            public void callback() {
                runnable.run();
            }

            @Override
            public boolean asPrimary() {
                return true; // mail is primary business
            }
        });

        // Try providers in order of preference
        List<RdmaProvider> providers = Arrays.asList(new DisniRdmaProvider(), // InfiniBand/RoCE - highest performance
                new TcpRdmaProvider() // TCP fallback - always available
        );

        for (RdmaProvider provider : providers) {
            if (provider.isAvailable()) {
                log.info("Selected RDMA provider: {}", provider.getProviderName());

 * **Synchronous:** your thread blocks until the response is readable.
 * **Asynchronous:** you enqueue the request on any thread, and get [called back](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-callback/) on another thread when the response is readable.

        public RequestOptionCall<DeleteRequestBuilder> deleteOption() {
            return deleteOption;
        }
    }

    @FunctionalInterface
    public interface RequestOptionCall<OP> {
        void callback(OP op);
    }

            // we called sizeIfKnown and when we started reading the file (or I guess if
            // maxCharsPerByte is wrong)
            // Fallback to an incremental approach
            StringBuilder builder = new StringBuilder(bufIndex + 32);
            builder.append(buffer, 0, bufIndex);
            buffer = null; // release for gc

        override fun enqueue(responseCallback: Callback) = TODO()

        override fun cancel() = TODO()

        override fun isExecuted(): Boolean = TODO()

        override fun isCanceled(): Boolean = TODO()

        override fun timeout(): Timeout = TODO()

        override fun clone(): Call = TODO()
      }
  }

  @Test
  fun callback() {
    val callback =
      object : Callback {

        public RequestOptionCall<DeleteRequestBuilder> deleteOption() {
            return deleteOption;
        }
    }

    @FunctionalInterface
    public interface RequestOptionCall<OP> {
        void callback(OP op);
    }

        public RequestOptionCall<DeleteRequestBuilder> deleteOption() {
            return deleteOption;
        }
    }

    @FunctionalInterface
    public interface RequestOptionCall<OP> {
        void callback(OP op);
    }

  /** The timestamp of the last taken event, used to measure elapsed time between events. */
  private var lastTimestampNs: Long? = null

  /** Confirm that the thread does not hold a lock on `lock` during the callback. */
  fun forbidLock(lock: Any) {
    forbiddenLocks.add(lock)
  }

  /**
   * Removes recorded events up to (and including) an event is found whose class equals [eventClass]
   * and returns it.
   */