Identifying event as first in stream for reset projected stream

This is the metadata for the first event for a stream that is emitted from a projection.  Do any of
these variables help me identify that this is the first event?  I can't rely on event number === 0
because on a reset projection the first event will typically by > 0.

  "$v": "5:7:7:3",
  "$c": 1694853,
  "$p": 1694853,
  "$s": {
    "accountInitialized": -1
  "$causedBy": "3e9b4d4a-3655-bc59-9a4b-123753845011"

I just realized I could use state in the projection to solve this.