class HalfOpen : CircuitBreaker.State
The CircuitBreaker is in HalfOpen state while it’s allowing a test request to go through.
- All other requests made while the test request is still running will short-circuit/fail-fast.
- If the `test request` succeeds, then the [CircuitBreaker](../../index.html) is tripped back into [Closed](../-closed/index.html), with the reset timeout, and the failures count also reset to their initial values.
- If the `test request` fails, then the [CircuitBreaker](../../index.html) is tripped back into [Open](../-open/index.html), the resetTimeout is multiplied by the exponentialBackoffFactor, up to the configured maxResetTimeout.