When conforming to Claims protocol, it's quite useful to define encode(). In the default implementation of encode() (https://github.com/IBM-Swift/Swift-JWT/blob/master/Sources/SwiftJWT/Claims.swift#L78-L83), a custom Base-64 decoder is called via base64urlEncodedString() but this is not public so inaccessible for user implementations of encode().

If this custom implementation of Base-64 encoding is useful generally, should it be public so user implementations of encode can use it?