func (r *Raft) BootstrapCluster(configuration Configuration) Future {
	bootstrapReq := &bootstrapFuture{}
	bootstrapReq.init()
	bootstrapReq.configuration = configuration
	select {
	case <-r.shutdownCh:
		return errorFuture{ErrRaftShutdown}
	case r.bootstrapCh <- bootstrapReq:
		return bootstrapReq
	}
}
func (r *Raft) BootstrapCluster(configuration Configuration) Future {
	bootstrapReq := &bootstrapFuture{}
	bootstrapReq.init()
	bootstrapReq.configuration = configuration
	select {
	case <-r.shutdownCh:
		return errorFuture{ErrRaftShutdown}
	case r.bootstrapCh <- bootstrapReq:
		return bootstrapReq
	}
}
// BootstrapCluster is equivalent to non-member BootstrapCluster but can be
// called on an un-bootstrapped Raft instance after it has been created. This
// should only be called at the beginning of time for the cluster, and you
// absolutely must make sure that you call it with the same configuration on all
// the Voter servers. There is no need to bootstrap Nonvoter and Staging
// servers.