# Wasmer Middlewares
The `wasmer-middlewares` crate is a collection of various useful
middlewares:
- `metering`: A middleware for tracking how many operators are
executed in total and putting a limit on the total number of
operators executed.
[See the `metering`
example](https://github.com/wasmerio/wasmer/blob/master/examples/metering.rs)
to get a concrete and complete example.