Correlation with business key or correlation variables

Reading the REST API on /message its not clear for process instances that if we supply both a business key and correlationkeys/localCorrelationKeys, is this a kind of filtering mechanism?

e.g. businesskey matches a single process instance, but correlation keys are also supplied, and they don’t match, what happens in this context?

Thanks, Conor.

Just reviewed the RuntimeService JAVA DOC, it clarifies that that businessKey is used to restrict the set of process instances, and correlationKeys are used to match the against variables in those processes.

REST API is not as explicit.