Minor API changes:
* gateway.NewRateLimiterHandler and gateway.NewConnectionRateLimiterHandler have
been replaced with gateway.NewRateLimitHandler.
* The handlers returned by both gateway.NewRateLimitHandler and the primary
gateway.Handler return an http.Handler augmented with a Shutdown(ctx) method
to be used for graceful cleanup of resources.
Fix:
* --per-conn-rate-limit was previously applied as a global rate limiter,
effectively making it have the same impact as --rate-limit. This change fixes
the behaviour such that --per-conn-rate-limit is applied as a API call
limiter within a single connection (i.e. a WebSocket connection). The rate
is specified as tokens-per-second, where tokens are relative to the expense
of the API call being made.
