Add Impression Events

[sighphyre]

This is a feature that's implemented in most of the Unleash SDKs, it's currently not implemented here.

Reference documentation here: https://docs.getunleash.io/reference/impression-data

And reference PR implementing this in the dotnet SDK: Unleash/unleash-client-dotnet#113

[ivanklee86]

What event system would you like to use? I haven't used them much myself, but from a quick Google it doesn't look like there's a clear favorite.

blinker seems reasonably popular, updated, and parts of the pallets project.

[sighphyre]

Honestly, I'm in exactly the same boat. I've never needed an event system in Python so I have no opinions here.

Blinker looks pretty reasonable. I think we should go with that

[ivanklee86]

eventsourcing is another one!

(Just tossing research here while I 🤔

[ivanklee86]

@sighphyre What GUID format do you expect for events? Here are the standard options for Python.

[sighphyre]

@sighphyre What GUID format do you expect for events? Here are the standard options for Python.

Any reason not to use a uuidv4()? That's my go to unless I need something special

[ilee-asapp]

I have seen some tweaks (i.e. namespacing) for massively distributed systems...but I suspect in most cases it's overkill and When we're Google... thinking. 😭

I'll start with uuidv4() and we can see how if it fowls up in the wild...