NewEtcdBackend constructs a etcd backend using a given machine address.

The amount of time to wait between the semaphore key renewals.

The lock TTL matches the default that Consul API uses, 15 seconds.

The delimiter is the same as the `-C` flag of etcdctl.

Ideally, this prefix would match the "_" used in the file backend, but that prefix has special meaning in etcd.

The lock prefix can (and probably should) cause an entry to be excluded from directory listings, so "_" works here.

The amount of time to wait if a watch fails before trying again.

The number of times to re-try a failed watch before signaling that leadership is lost.

Etcd2Backend is a physical backend that stores data at specific prefix within etcd.

Etcd2Lock implements a lock using and Etcd2 backend.

EtcdBackend is a physical backend that stores data at specific prefix within etcd.

EtcdLock implements a lock using and etcd backend.