Supporting SSE "edge.stale" config events

This release supports the new config SSE events, which can instruct the streaming client to disconnect when the edge has become "stale".

More permissive with CIDRs

This release makes it the IP-Address comparisons more permissive with the format for CIDRs (they no longer require a mask).

Thanks @ownercoder for your PR!

Allowing a user-defined error handler func

The user can now provide their own ErrorFunc to handle asynchronous errors. The default one logs a fatal error, but this may not always be desirable.

Thanks @luvLinux for raising this

Improving usability of ClientWithContext

The FeatureHub SDKs are "context-first", and this PR makes the Go SDK more strongly aligned with this

• Moved the bulk of the streaming client code into a separate package
• Brought the ClientWithContext into line with our Client interface (all methods now supported)
• Examples in README.md updated to reflect this
• Added methods to still allow access to the underlying client if required

Being more accepting of numeric types

Prior to this version numeric strategies could only be evaluated with float64 values. We now attempt to assert and cast numeric types sensibly, although we still have an issue with float32 comparisons (due to differences in precision).

1.3.1

• Support for userkey attribute-based rules

The Go SDK gets its own repo!

Importing the Go client SDK from the FeatureHub monorepo, so now we can manage semver for Go-specific point releases.