Chapter 8's RedisClient example

In chapter 8 (_Async Streams_ >> _Event Emitters_, on pages 185-186) you have defined the following two types:
```ts
type Events = {    
ready: void    
error: Error    
reconnecting: {
delay: number, 
attempt: number
}
}

type RedisClient = {    
on(event: E, f: (args: Events[E]) => void): void
}
```

I would like to have a naive implementation like this:
```ts
let Client: RedisClient = {        
on(event: E, f: (args: Events[E]) => void) {
        if(event === "reconnecting") {
           f({delay: 1, attempt: 1})
     }    
}
}
Client.on("reconnecting", (param :{delay: number, attempt: number}) => console.log(param.delay))
```
Unfortunately it gives me the following error (at this `f({delay: 1, attempt: 1})` line):
```
Argument of type '{ delay: number; attempt: number; }' is not assignable to parameter of type 'Events[E]'.
Type '{ delay: number; attempt: number; }' is not assignable to type 'void & Error & { delay: number; attempt: number; }'.
Type '{ delay: number; attempt: number; }' is not assignable to type 'void'.(2345)
```
It seems like it uses intersection instead of union. How can I fix this?

I've found a related [Typescript issue](https://github.com/microsoft/TypeScript/issues/31904), but I couldn't manage to apply the suggested workaround in this example. Can you help me with this please?