The type of postMessage is too permissive

[gbagan]

@JordanMartinez

In the current implementation of web-workers, worker # postMessage a accepts any type for a.
But, in the documentation, it is said that the posted message must be serializable which is equivalent to be a correct input of
structuredClone.
So I propose to implement a type class Serializable
and replace the signature of postMessage with

forall a. Serializable a => a -> Worker -> Effect Unit

@natefaubion said that it implemented something similar in
https://github.com/natefaubion/purescript-node-workerbees/blob/main/src/Node/WorkerBees.purs#L112-L150

[JordanMartinez]

Any reason why we don't just use Sendable?

[gbagan]

No reason, Sendable is nice

[JordanMartinez]

I think we should call the class IsSendable because it's just a boolean check at the type-level. That will also make it differ from Nate's library's class name.

[gbagan]

I close this issue since it has been fixed.