public <K, V> Window create(Region<K, V> region, DistributedMember sink, int windowSize) {
    WindowImpl<K, V> w = new WindowImpl<>(region, sink, windowSize);
    int id = processors.put(w);

    w.setWindowId(id);
    return w;
  }
Creates and registers a {@link Window} that provides flow control.

@param region the region
@param sink the data recipient
@param windowSize the size of the sliding window

@see #sendAbort(DistributionManager, int, DistributedMember)
@see #sendAck(DistributionManager, DistributedMember, int, String)
geode-core/src/main/java/org/apache/geode/internal/cache/snapshot/FlowController.java