qbit/core/src/main/java/io/advantageous/qbit/reactive/CallbackBuilder.java
public <K, V> CallbackBuilder withMapCallback(final Class<K> keyClass,
                                                  final Class<V> valueClass,
                                                  final Callback<Map<K, V>> callback) {
        this.callback = callback;
        return this;
    }
public <K, V> CallbackBuilder withMapCallback(final Class<K> keyClass,
                                                  final Class<V> valueClass,
                                                  final Callback<Map<K, V>> callback) {
        this.callback = callback;
        return this;
    }
Builder method to set callback handler that takes a map

@param keyClass   keyClass
@param valueClass valueClass
@param callback   callback
@param <K>        key type
@param <V>        value type
@return this