libmpack0 binary package in Ubuntu Focal riscv64

 libmpack is a small binary serialization/RPC library that implements both the
 msgpack and msgpack-rpc specifications.
 .
 Differences from msgpack-c:
 .
  * Callback-based API to simplify (de)serialization directly to/from
    application-specific objects.
  * C89 compatible code
  * No allocation performed by the library, but helpers to simplify dynamic
    allocation if the application needs it.
  * Non-backtracking, incremental/iterative parse/serialization API

Source package