dio_single_flight 0.1.1

Automatic token refresh for Dio: one refresh for concurrent 401s, automatic replay of failed requests, and clean failure with no hangs.

0.1.0

Initial release.

• Single-flight refresh — only one refresh call runs at a time, no matter how many requests fail with 401 concurrently; all failed requests wait for it and are replayed with the new token.
• Safe replay — the original RequestOptions is never mutated; FormData is cloned so retried uploads work. Requests that 401 again after a retry are passed through to the caller (no infinite loops).
• Race guard — a 401 arriving after a refresh already completed (its request was dispatched with the stale token) is replayed immediately without triggering a second refresh.
• Terminal vs transient failures — terminal failures (per AuthRefreshConfig.isTerminalRefreshError: by default AuthRefreshException with retryable == false, or refresh-endpoint 400/401/403 responses) are memoized for the sent access token and fire onAuthFailed exactly once; later 401s with the same token are rejected with the memoized failure until the stored tokens change. Transient failures (timeouts, connection errors, 5xx responses) reject waiters with AuthRefreshException(retryable: true) and never fire onAuthFailed or get memoized — the next 401 starts a fresh cycle.
• Session protection — logout (or logout-then-login) during a refresh discards the stale result; 401s straggling in after a logout are rejected immediately without refreshing.
• Cancellation — a request cancelled while waiting for the refresh rejects immediately with DioExceptionType.cancel; the refresh continues for the remaining waiters.
• No deadlocks — plain Interceptor with a single-flight coordinator instead of QueuedInterceptor locking; refreshes run on a dedicated Dio (custom adapters, proxies and certificate pinning preserved) with no interceptor recursion.