List of things left for later:
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 * qmi-codegen: Skip additional heap allocation for Strings marked with
   'max-size'. If the 'max-size' is short enough, we can just use arrays of
   gchars with a specific size directly in the input/output bundle.

 * dms: Support 'Preferred Roaming List' TLV (0x13) in DMS/"Activate Manual".
   This TLV is based on an array of raw binary data which can be passed to the
   device over multiple messages, using a sequence number to identify each
   passed chunk. Probably not worth handling this specific case in qmi-codegen.
   Also, sending such a message should trigger internally multiple messages
   being sent automatically, not just one.

 * qmicli: Implement `--dms-activate-manual'.