@JsonIgnore
    public String getStreamMetaValue(final String metaKey) {
        return NullSafe.isNonBlankString(metaKey)
                ? streamMetaData.get(CIKey.of(metaKey))
                : null;
    }
Represents the hashed form of a Data Feed Key, i.e. where we only have the
hash of the key and not the key itself.
stroom-receive/stroom-receive-common/src/main/java/stroom/receive/common/HashedDataFeedKey.java