January 23, 2019. “Event processing” is a model that allows you to decouple your microservices by using a message queue. Rather than connecting directly to a service, which may or may not be at a known location, you broadcast and listen to queued events, through Redis, Amazon SQS, RabbitMQ, Apache Kafka, and a whole host of other sources. The size in bytes of region being filled in buffer and must be a multiple of pattern_size. event_wait_list , num_events_in_wait_list ... with command_queue and buffer are not the same or if the context associated with command_queue and events in event_wait_list are not the same. CL_INVALID_MEM_OBJECT if.