Instance Method
cachedOrNewToken()
Return the cached token if still valid (with a 60-second buffer), otherwise generate and cache a new one.
func cachedOrNewToken() async throws -> StringReturn Value
A valid JWT token string.
Discussion
Concurrent callers that both observe a cache miss share a single in-flight Task so only one JWT signing operation is performed at a time.
Throws
ShipItError.jwtGenerationFailed(underlying:) if signing fails.