Invoke calls the given APICall, performing retries as specified by opts, if any.

OnCodes returns a Retryer that retries if and only if the previous attempt returns a GRPC error whose error code is stored in cc.

Sleep is similar to time.Sleep, but it can be interrupted by ctx.Done() closing.

WithRetry sets CallSettings.Retry to fn.

XGoogHeader is for use by the Google Cloud Libraries only.

Backoff implements exponential backoff.

CallOption is an option used by Invoke to control behaviors of RPC calls.

Retryer is used by Invoke to determine retry behavior.

A user defined call stub.