TODO

golint
RateLimit interface
- add https://godoc.org/golang.org/x/time/rate implementation
- RateLimit.Wait() support context for supporting cancellation.
Eliminate duplicated log. logging levels in Get()/Handle():
- info: entry(for auditing)
- debug: success return
- error: failure return
- warn: context.Done()
- debug: others
Improve API for CircuitBreaker config, register, flush.
Reduce dependencies(exported symbols) to external packages like clock.
Alternative circuitbreaker implementation https://github.com/rubyist/circuitbreaker
metrics using expvar

Done

Opts passed by addr
Make Xxxxtream/Handler xXXXStgream/Handler
NewMockHandler/Stream(*mock.Mock)
Remove Semaphore because it blocks so it's not resilient. Or move it to package extra
Improve Observe(value, labels, optional data). remove Unused MX_XXXX.
Remove/export noopLogger
Package-wise setLogger()
opentracing
- Span an be obtain from context.
- Abstract logger to optionally writes to SpanContext.
Add context support.
- context should not be embedded in Message, since context propagation is normally one-way(parent to children).

Rename Bulkhead. Currently it employs semaphore isolation, because the calling thread executes the client libs/backends
- https://github.com/Netflix/Hystrix/wiki/How-it-Works#Isolation
- https://stackoverflow.com/questions/30391809/what-is-bulkhead-pattern-used-by-hystrix
Have a look at https://github.com/trustmaster/goflow. Inter-op?