6acec6b9ff multiprocess: Add type conversion code for UniValue types (Ryan Ofsky)
0cc74fce72 multiprocess: Add type conversion code for serializable types (Ryan Ofsky)
4aaee23921 test: add ipc test to test multiprocess type conversion code (Ryan Ofsky)
Pull request description:
Add type conversion hooks to allow `UniValue` objects, and objects that have `CDataStream` `Serialize` and `Unserialize` methods to be used as arguments and return values in Cap'nProto interface methods. Also add unit test to verify the hooks are working and data can be round-tripped correctly.
The non-test code in this PR was previously part of #10102 and has been split off for easier review, but the test code is new.
---
This PR is part of the [process separation project](https://github.com/bitcoin/bitcoin/issues/28722).
ACKs for top commit:
achow101:
ACK 6acec6b9ff
dergoegge:
reACK 6acec6b9ff
Tree-SHA512: 5d2cbc5215d488b876d34420adf91205dabf09b736183dcc85aa86255e3804c2bac5bab6792dacd585ef99a1d92cf29c8afb3eb65e4d953abc7ffe41994340c6