Support `lengthTBQueue` by storing the initial capacity

[haskell]

Support `lengthTBQueue` by storing the initial capacity

[Fuuzetsu]

Why not just hold onto this value yourself? Even wrap the queue in a data type if you're feeling fancy.

[mitchellwrosen]

Holding onto the initial capacity isn't enough since you can't get the TBQueue's inner read/write capacity vars either.

But to your point, yes you can make your own type and track the capacity with a TVar:

data MyTBQueue a = MyTBQueue (TBQueue a) (TVar Int)

[simonmar]

Seems reasonable to me. Someone want to submit a PR?

[Fuuzetsu]

Right you'd make reads and writes on this own datatype. Either way 🤷