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# backendMethod

The I/O multiplexer method libevent selected at initialization time.

```
var backendMethod: String { get }
```

## Return Value

`"kqueue"` on Apple platforms, `"epoll"` on Linux, `"poll"` or
`"select"` as fallbacks, or `"unknown"` if libevent reports no method.

## Discussion> SeeAlso: <doc://Event/documentation/Event/BackendAndPlatforms> for the invariant enforced by the
> `EventLoop uses optimal backend` test.