@Override
  public void setLeaderElectorListener(LeaderElectorListener listener) {
    this.leaderElectorListener = listener;
  }
Class to facilitate leader election in Azure.
The processor that acquires the lease on the blob becomes the leader.
The lease ID is null initially. It is generated by Azure when the processor acquires the lease, and updated accordingly.
Every processor requires a valid active lease ID in order to perform successful write and delete operations on the blob.
Read operations from the blob are not dependent on the lease ID.
samza-azure/src/main/java/org/apache/samza/coordinator/AzureLeaderElector.java