Caches wasm instances. Reusing wasm instances allows maximum speed in function
calls but also introduces the possibility of memory corruption or other bad
state that is inappropriate to persist/reuse/access across calls. It is the
responsibility of the host to discard instances that are not eligible for reuse.
Caches wasmer modules that can be used to build wasmer instances. This is the
output of building from wasm or deserializing the items in the serialized module cache.
Cache for serialized modules. These are fully compiled wasm modules that are
then serialized by wasmer and can be cached. A serialized wasm module must still
be deserialized before it can be used to build instances. The deserialization
process is far faster than compiling and much slower than instance building.