@Override
        public boolean equals(Object o) {
            if (this == o) return true;
            if (!(o instanceof DistributedHerderRequest))
                return false;
            DistributedHerderRequest other = (DistributedHerderRequest) o;
            return compareTo(other) == 0;
        }
Execute the given action and subsequent callback immediately if the current thread is the herder's tick thread,
or use them to create and store a {@link DistributedHerderRequest} on the request queue and return the resulting request
if not.
@param action the action that should be run on the herder's tick thread
@param callback the callback that should be invoked once the action is complete
@return a new {@link DistributedHerderRequest} if one has been created and added to the request queue, and {@code null} otherwise
connect/runtime/src/main/java/org/apache/kafka/connect/runtime/distributed/DistributedHerder.java