Enhance the probe mechanism in circuit breaker

[louyuting]

Issue Description

Type: feature request

Describe what feature you want

Currently, the circuit breaker implement based on state machine. Details refer to #122

1. Probing from Open to Half-Open only once. If succeed to probe, changes state to Closed, if not, changes state back to Open.
2. Timeout of probing is fixed. Maybe need somehow backoff to optimize the probe mechanism

Additional context

Add any other context or screenshots about the feature request here.