cassandra map，无法将字符串解码为UTF8：

Question

我正在尝试将二进制数据存储到Cassandra DB，这是描述

CREATE TABLE first.block (
        uuid text PRIMARY KEY,
        data map<bigint, blob>
) WITH bloom_filter_fp_chance = 0.01
        AND caching = '{"keys":"ALL", "rows_per_partition":"NONE"}'
        AND comment = ''
        AND compaction = {'class':         'org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy'}
        AND compression = {'sstable_compression': 'org.apache.cassandra.io.compress.LZ4Compressor'}
        AND dclocal_read_repair_chance = 0.1
    AND default_time_to_live = 0
    AND gc_grace_seconds = 864000
    AND max_index_interval = 2048
    AND memtable_flush_period_in_ms = 0
    AND min_index_interval = 128
    AND read_repair_chance = 0.0
    AND speculative_retry = '99.0PERCENTILE';

我正在尝试保存blob类型的数据，但是在尝试为Cassandra编写C驱动程序时，我收到错误无法将字符串解码为UTF8：，
我相信blob类型需要没有验证，因为它是字节类型。 我对Cassandra很新，请帮忙， 谢谢