@Override
        public V setValue(V value) {
            // This would be inefficient to support since we'd need a back-reference
            // to the enclosing map in each Entry object.  There would also be
            // complications if this entry object was sourced from a historical iterator;
            // we don't support modifying the past.  Since we don't really need this API,
            // let's just not support it.
            throw new UnsupportedOperationException();
        }
This is a hash map which can be snapshotted.
<br>
See {@link SnapshottableHashTable} for more details about the implementation.
<br>
This class requires external synchronization.  Null keys and values are not supported.

@param <K>   The key type of the set.
@param <V>   The value type of the set.
server-common/src/main/java/org/apache/kafka/timeline/TimelineHashMap.java