When you aggregate messages, you combine a number of response messages
from the invocation of one or more services into a single message. When you
broadcast messages you send notification to the service and do not expect
a response.
Before you begin
The most common way to aggregate messages is to use Fan Out and Fan
In primitives in combination. Another way to aggregate messages is to perform
a chained aggregation using Service Invoke. You broadcast messages using the
Fan Out primitive.