dio_essentials: a Dart package bundling four Dio interceptors for dedup, retries, token refresh and logging

Many Dio-based apps end up writing the same four interceptors by hand: retry, auth token injection with refresh on 401, logging, and request deduplication. These hand-rolled versions often carry common bugs, such as linear retry delays that are zero on the first attempt, retrying POSTs that may duplicate server writes, and refreshing the token once per concurrent request. The dio_essentials package, a pure Dart library whose only dependency is dio and which runs on VM, Flutter and web, provides all four interceptors designed to avoid these pitfalls. Its features include merging identical in-flight GET requests, exponential backoff with full jitter that honors Retry-After, a single coordinated token refresh with session-expiry handling, and a logger that redacts sensitive headers, query parameters and JSON keys. It is installed from its GitHub repository, and the README stresses that interceptor order matters.