private void send(String key, ComplexEvent event) {
        if (key != null) {
            SiddhiAppContext.startPartitionFlow(key);
            try {
                partitionRuntime.initPartition();
                streamJunctionMap.get(streamId).sendEvent(event);
            } finally {
                SiddhiAppContext.stopPartitionFlow();
            }
        }
    }
Specific {@link StreamJunction.Receiver} implementation to pump events into partitions. This will send the event
to the matching partition.
modules/siddhi-core/src/main/java/io/siddhi/core/partition/PartitionStreamReceiver.java