How can I access shared memory within an imported function?

[john01dav]

In order to do most interesting things it is necessary to have an ABI that allows imported functions to read shared memory. For example, if the WASM code wants to pass a string to the host code it can give a pointer and length, which the host code can then read within the body of the imported function. But, when I am trying to write this, I am running into an issue. In order to get a MemoryView I need a & reference to the store, but I need to give a &mut reference to the store in Function::call or TypedFunction::call, which precludes having this & reference. How can I implement such an ABI?