Calling textAsBlob on an ascii field results in com.datastax.oss.driver.api.core.type.codec.CodecNotFoundException: Codec not found for requested operation: [BLOB <-> java.lang.String]

[paayers]

When migrating, we have a column 'node_id' that is held in an ascii field, but we need to compress those and store in a blob field, however CDM isn't able to convert the ascii field to a blob on the fly, and we get:
com.datastax.oss.driver.api.core.type.codec.CodecNotFoundException: Codec not found for requested operation: [BLOB <-> java.lang.String]

The source schema with node_id as an ascii field is this:

CREATE TABLE v2metrics_downsampled.per_node_3m_0 (
    metric_id blob,
    bucket_ts int,
    bucket_idx tinyint,
    node_id ascii,
    row_type tinyint,
    value blob,
    PRIMARY KEY ((metric_id, bucket_ts), bucket_idx, node_id, row_type)
) WITH CLUSTERING ORDER BY (bucket_idx ASC, node_id ASC, row_type ASC)
    AND additional_write_policy = '99p'
    AND bloom_filter_fp_chance = 0.01
    AND caching = {'keys': 'ALL', 'rows_per_partition': 'NONE'}
    AND cdc = false
    AND comment = ''
    AND compaction = {'class': 'org.apache.cassandra.db.compaction.TimeWindowCompactionStrategy', 'compaction_window_size': '24', 'compaction_window_unit': 'HOURS', 'max_threshold': '32', 'min_threshold': '4', 'tombstone_threshold': '0.8', 'unchecked_tombstone_compaction': 'true', 'unsafe_aggressive_sstable_expiration': 'true'}
    AND compression = {'chunk_length_in_kb': '64', 'class': 'org.apache.cassandra.io.compress.LZ4Compressor'}
    AND crc_check_chance = 1.0
    AND default_time_to_live = 2419200
    AND extensions = {}
    AND gc_grace_seconds = 3600
    AND max_index_interval = 2048
    AND memtable_flush_period_in_ms = 0
    AND min_index_interval = 128
    AND read_repair = 'BLOCKING'
    AND speculative_retry = '99p';

The target schema where node_id is a blob is simply:

CREATE TABLE v2metrics_downsampled.per_node_3m_0 (
    metric_id blob,
    bucket_ts int,
    bucket_idx tinyint,
    node_id blob,
    row_type tinyint,
    value blob,
    PRIMARY KEY ((metric_id, bucket_ts), bucket_idx, node_id, row_type)
) WITH CLUSTERING ORDER BY (bucket_idx ASC, node_id ASC, row_type ASC)
    AND additional_write_policy = '99p'
    AND bloom_filter_fp_chance = 0.01
    AND caching = {'keys': 'ALL', 'rows_per_partition': 'NONE'}
    AND cdc = false
    AND comment = ''
    AND compaction = {'class': 'org.apache.cassandra.db.compaction.TimeWindowCompactionStrategy', 'compaction_window_size': '24', 'compaction_window_unit': 'HOURS', 'max_threshold': '32', 'min_threshold': '4', 'tombstone_threshold': '0.8', 'unchecked_tombstone_compaction': 'true', 'unsafe_aggressive_sstable_expiration': 'true'}
    AND compression = {'chunk_length_in_kb': '64', 'class': 'org.apache.cassandra.io.compress.LZ4Compressor'}
    AND crc_check_chance = 1.0
    AND default_time_to_live = 2419200
    AND extensions = {}
    AND gc_grace_seconds = 3600
    AND max_index_interval = 2048
    AND memtable_flush_period_in_ms = 0
    AND min_index_interval = 128
    AND read_repair = 'BLOCKING'
    AND speculative_retry = '99p';
    ```

Being able to perform conversions like this would be super helpful.
Thanks