@Override
  public boolean equals(Object obj) {
    if (obj == null) {
      return false;
    }
    if (this == obj) {
      return true;
    }
    if (!(obj instanceof ProgressIndex)) {
      return false;
    }
    return this.equals((ProgressIndex) obj);
  }
A.equals(B) is true if and only if A, B are both {@link ProgressIndex} and A.equals(({@link
ProgressIndex})B) is true.

@param obj the object to be compared
@return true if and only if this progress index is equal to the given object
iotdb-core/node-commons/src/main/java/org/apache/iotdb/commons/consensus/index/ProgressIndex.java