@RestrictedApi(explanation = "Should only be called in tests", link = "",
      allowedOnPath = ".*(/src/test/.*|TestSnapshotProcedure).java")
  boolean inRetrying() {
    return retryCounter != null;
  }
A remote procedure which is used to send region snapshot request to region server. The basic
logic of SnapshotRegionProcedure is similar like {@link ServerRemoteProcedure}, only with a
little difference, when {@link FailedRemoteDispatchException} was thrown, SnapshotRegionProcedure
will sleep some time and continue retrying until success.
hbase-server/src/main/java/org/apache/hadoop/hbase/master/procedure/SnapshotRegionProcedure.java