This PR introduces Wasm ops. These calls are optimized for entry from
Wasm land.
The `#[op(wasm)]` attribute is opt-in.
Last parameter `Option<&mut [u8]>` is the memory slice of the Wasm
module *when entered from a Fast API call*. Otherwise, the user is
expected to implement logic to obtain the memory if `None`
```rust
#[op(wasm)]
pub fn op_args_get(
offset: i32,
buffer_offset: i32,
memory: Option<&mut [u8]>,
) {
// ...
}
```
Implements fast scheduling of deferred op futures.
```rs
#[op(fast)]
async fn op_read(
state: Rc<RefCell<OpState>>,
rid: ResourceId,
buf: &mut [u8],
) -> Result<u32, Error> {
// ...
}
```
The future is scheduled via a fast API call and polled by the event loop
after being woken up by its waker.
