Reintroduce support for decoding legacy msgpack encoding
The full contents of the journal are encoded with this schema, so we should keep supporting it
Test Plan
new unit test added
Migrated from D2715 (view on Phabricator)
Staging instance, all changes can be removed at any time
The full contents of the journal are encoded with this schema, so we should keep supporting it
new unit test added
Migrated from D2715 (view on Phabricator)