private void writeAssignedSnapshotSplits(
            Map<String, SchemalessSnapshotSplit> assignedSplits, DataOutputSerializer out)
            throws IOException {
        final int size = assignedSplits.size();
        out.writeInt(size);
        for (Map.Entry<String, SchemalessSnapshotSplit> entry : assignedSplits.entrySet()) {
            out.writeUTF(entry.getKey());
            byte[] splitBytes = splitSerializer.serialize(entry.getValue());
            out.writeInt(splitBytes.length);
            out.write(splitBytes);
        }
    }
The {@link SimpleVersionedSerializer Serializer} for the {@link PendingSplitsState}.
Copy from com.ververica:flink-cdc-base:2.3.0.
inlong-sort/sort-flink/cdc-base/src/main/java/org/apache/inlong/sort/cdc/base/source/assigner/state/PendingSplitsStateSerializer.java