No Eq or PartialEq for SecretKey

[ilya-bobyr]

It seems to be intentional that SecretKey does not have Eq defined for it.
But the reasoning is not part of the type documentation.
Nor was I able to find a discussion elsewhere.

This issue seems related: #52
It says:

There's functionality in the subtle crate for comparing the equality of two equally-sized byte arrays in constant time, if you need to check if two secret keys are the same.

Is it the case that nobody just connected the crates, to use subtle as an implementation of Eq for SecretKey?
Or is there more to it?

I think it would be nice to have an explanation. Either as an issue or directly in the doc-comment.
I would imagine, I might not be the only person looking for Eq.

[based-a-tron]

They return different types.
ConstantTimeEq's ct_eq returns a Choice, to prevent things like the following toy example from leaking timing information by short circuiting, or through other side channels
if (secret_key1 == key1) && (secret_key2 == key2) { ... }

[rozbb]

SecretKey is just a 32-byte array in 2.0