trackAction name while migrating to iOS SDK 4.x

Hello Adobe Community !

We are updating our app to the 4.x iOS library.

I am trying to understand the role of "action" name in trackAction. I understood from the Adobe document that "actions" are the events that we want to measure.

Is it mandatory to set action value ?  Where can we see it in Lifecycle metrics ?

Suppose I want to track "Help" link click action,

what should we pass as action name to trackAction method? Is it user defined ?

In previous SDK, we were passing action name in Prop but in 4.x SDK, do we have to pass that Prop value as an action name in trackAction method?

For example:

Previous method:

ADBMobile.trackLink({prop1="Help Link Click"});

New method:

ADBMobile.trackAction("Help Link Click", {prop1="Help Link Click"});

is this correct or we can remove additional prop1 data from trackAction method?

If we pass the action name, do we have to again pass that value in additional data parameter?

If we pass "nil" value in action name and prop1 as additional parameter, would it affect Adobe Report Data ?

For example:

ADBMobile.trackAction(nil, {prop1="Help Link Click"});

Thank you for the help.

Thank You,

Pre L.