void callback(CQ query, CF filter);
    }

    @FunctionalInterface
    public interface OperatorCall<CQ extends EsAbstractConditionQuery> {

        void callback(CQ query);
    }

    @FunctionalInterface
    public interface ScoreFunctionCall<CC extends ScoreFunctionCreator<?>> {

        void callback(CC creator);
    }

    @FunctionalInterface

                if (builderEntityCall != null) {
                    builderEntityCall.callback(builder);
                }
                bulkBuilder.add((IndexRequestBuilder) builder);
            } else if (builder instanceof UpdateRequestBuilder) {
                if (builderEntityCall != null) {
                    builderEntityCall.callback(builder);
                }
                bulkBuilder.add((UpdateRequestBuilder) builder);

import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.Proxy;
import java.util.List;
import java.util.concurrent.atomic.AtomicLong;
import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.Connection;
import okhttp3.EventListener;
import okhttp3.Handshake;
import okhttp3.HttpUrl;
import okhttp3.OkHttpClient;
import okhttp3.Protocol;
import okhttp3.Request;
import okhttp3.Response;

import okhttp3.Call
import okhttp3.Callback
import okhttp3.Response
import okhttp3.internal.closeQuietly
import okio.IOException

suspend fun Call.executeAsync(): Response =
  suspendCancellableCoroutine { continuation ->
    continuation.invokeOnCancellation {
      this.cancel()
    }
    this.enqueue(
      object : Callback {
        override fun onFailure(
          call: Call,

        }
    }

    /**
     * Flushes configuration files to the search engine and executes a callback.
     *
     * @param callback the callback to execute after flushing
     */
    public void flushConfigFiles(final Runnable callback) {
        final FessConfig fessConfig = ComponentUtil.getFessConfig();

        final String fesenType = fessConfig.getFesenType();

        void callback(CQ query, CF filter);
    }

    @FunctionalInterface
    public interface OperatorCall<CQ extends EsAbstractConditionQuery> {

        void callback(CQ query);
    }

    @FunctionalInterface
    public interface ScoreFunctionCall<CC extends ScoreFunctionCreator<?>> {

        void callback(CC creator);
    }

    @FunctionalInterface

        void callback(CQ query, CF filter);
    }

    @FunctionalInterface
    public interface OperatorCall<CQ extends EsAbstractConditionQuery> {

        void callback(CQ query);
    }

    @FunctionalInterface
    public interface ScoreFunctionCall<CC extends ScoreFunctionCreator<?>> {

        void callback(CC creator);
    }

    @FunctionalInterface

                if (builderEntityCall != null) {
                    builderEntityCall.callback(builder);
                }
                bulkBuilder.add((IndexRequestBuilder) builder);
            } else if (builder instanceof UpdateRequestBuilder) {
                if (builderEntityCall != null) {
                    builderEntityCall.callback(builder);
                }
                bulkBuilder.add((UpdateRequestBuilder) builder);

            logger.debug("Storing state in session: {}", stateData);
        }
        stateMap.put(state, stateData);
    }

    /**
     * Processes authentication data from the OAuth2 callback.
     * @param request The HTTP servlet request containing authentication data.
     * @return The login credential or null if processing fails.
     */

    * Send a notification back to the API user (the external developer), as a callback.
        * At this point is that the API will somehow send a POST request to the
            external API with the notification of the invoice event
            (e.g. "payment successful").
    """
    # Send the invoice, collect the money, send the notification (the callback)