@Override
  public EnabledTableSnapshotHandler prepare() throws Exception {
    return (EnabledTableSnapshotHandler) super.prepare();
  }
Handle the master side of taking a snapshot of an online table, regardless of snapshot type. Uses
a {@link Procedure} to run the snapshot across all the involved region servers.
@see ProcedureCoordinator
hbase-server/src/main/java/org/apache/hadoop/hbase/master/snapshot/EnabledTableSnapshotHandler.java