Scatter-Gather sends the event to each routes concurrently. Hence both route in this example will

start in parallel. So total time to complete processing is 40 seconds

The Scatter-Gather component is a routing event processor that processes a Mule event through

different parallel processing routes that contain different event processors. Each route receives a

reference to the Mule event and executes a sequence of one or more event processors. Each of these

routes uses a separate thread to execute the event processors, and the resulting Mule event can be

either the same Mule event without modifications or a new Mule event with its own payload,

attributes, and variables. The Scatter-Gather component then combines the Mule events returned by

each processing route into a new Mule event that is passed to the next event processor only after

every route completes successfully.

The Scatter-Gather component executes each route in parallel, not sequentially. Parallel execution of

routes can greatly increase the efficiency of your Mule application and may provide more

information than sequential processing.

Mule Ref Doc : https://docs.mulesoft.com/mule-runtime/4.3/scatter-gather-concept