Add log sequence attribute for timestamp tie-breaking

Environments like cloudlfare workers can employ "[time freeze](<https://developers.cloudflare.com/workers/reference/security-model/#step-1-disallow-timers-and-multi-threading>)" to mitigate against specter attacks.<br><br>One idea we had is to introduce a monotonically incrementing value as an attribute that we can use as a tie-breaker for those cases.