@Override
    public NetworkClientDelegate.PollResult poll(final long currentTimeMs) {
        // Copy the outgoing request list and clear it.
        List<NetworkClientDelegate.UnsentRequest> unsentRequests = new ArrayList<>(requestsToSend);
        requestsToSend.clear();
        return new NetworkClientDelegate.PollResult(unsentRequests);
    }
Determine if there are pending fetch offsets requests to be sent and build a
{@link NetworkClientDelegate.PollResult}
containing it.
clients/src/main/java/org/apache/kafka/clients/consumer/internals/OffsetsRequestManager.java