@Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        PartitionInfo other = (PartitionInfo) obj;
        return Objects.equals(topic, other.topic) &&
            partition == other.partition &&
            Objects.equals(leader, other.leader) &&
            Objects.deepEquals(replicas, other.replicas) &&
            Objects.deepEquals(inSyncReplicas, other.inSyncReplicas) &&
            Objects.deepEquals(offlineReplicas, other.offlineReplicas);
    }
The subset of the replicas that are offline
clients/src/main/java/org/apache/kafka/common/PartitionInfo.java