Lazy decoding

[stwiname]

Currently if you don't provide all the message types then data will fail to decode and indexing will stop.

We should only decode data as its needed (if it passes filters) so that if data is not needed because its filtered out we don't decode it. This may also have some performance improvements as we're not decoding as much data.

We should be able to do a lot of this with lazy loading https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/get#smart_self-overwriting_lazy_getters