Continuations use the @AuraEnabled annotation for Apex code. Here are the rules for usage.
@AuraEnabled(continuation=true)
An Apex controller method that returns a continuation must be annotated with @AuraEnabled(continuation=true).
@AuraEnabled(continuation=true cacheable=true)
To cache the result of a continuation action, set cacheable=true on the annotation for the Apex callback method.
There’s a space, not a comma, between continuation=true cacheable=true.
Note
Caching Considerations
It’s best practice to set cacheable=true on all methods involved in the continuation chain, including the method that returns a Continuation object.
In this example, the Apex method that returns the continuation, startRequest(), and the callback, processResponse(), both contain cacheable=true in their @AuraEnabled annotation.
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