Install the instrumented cache as the first caller WITHOUT owning the connection.
For the testing-CLI path: call this BEFORE initializeMJProvider() so the CLI's
own provider setup finds the cache already claimed (its StartupManager Initialize
no-ops) and every cache read/write flows through the instrumented wrapper.
Returns the instrumented storage, or null when the cache was ALREADY initialized
by something else (can't instrument retroactively — the caller decides whether to
proceed uninstrumented or abort).
Install the instrumented cache as the first caller WITHOUT owning the connection. For the testing-CLI path: call this BEFORE initializeMJProvider() so the CLI's own provider setup finds the cache already claimed (its StartupManager Initialize no-ops) and every cache read/write flows through the instrumented wrapper.
Returns the instrumented storage, or null when the cache was ALREADY initialized by something else (can't instrument retroactively — the caller decides whether to proceed uninstrumented or abort).