`iterable` type for event properties leads to exception in PhpStan

[zeleznypa]

Using iterable static type for event properties leads to Cannot access an offset on iterable<callable> exception in PhpStan

see: https://phpstan.org/r/d30bcff2-9ead-47d8-9a90-1e2a5443f39e

[zeleznypa]

As @ondrejmirtes wrote in Pehapkari Slack:

Because iterable is an array|Traversable. And o Traversable is not safe to do $foo[] = …