Summary

Appends can now be shaped by the caller instead of using fixed values.

Added

AppendOptions takes eventSourceType, eventStreamType, eventStreamId, subject, tags and occurred, so an append can target a non-default stream, carry tags, be backdated, or name the compliance subject. (#23)
AppendOptionsBuilder for constructing options from Java, where Kotlin's default arguments are unavailable. (#23)

The compliance subject was fixed to the event source id with no way to override it, so PII for a subject other than the event source could not be modeled from Kotlin or Java. (#23)