@Override
    public String toString() {
        return "PartitionReassignment(" +
                "replicas=" + replicas +
                ", addingReplicas=" + addingReplicas +
                ", removingReplicas=" + removingReplicas +
                ')';
    }
The brokers that we are removing this partition from as part of a reassignment.
A subset of replicas.
clients/src/main/java/org/apache/kafka/clients/admin/PartitionReassignment.java