Version - 0.0.3

This release fixes several bugs that affected real applications and adds
request cancellation. Most apps need no code changes; see "Behavior changes"
below. Note that ^0.0.2 does not allow 0.0.3; update your constraint to
^0.0.3.

Bug fixes

• Typed requests work. request<Map<String, dynamic>> (and any T other
  than dynamic) threw a TypeError on every adapter, after sending extra
  retry requests. Responses are now converted to ApiResponse<T>; data of
  the wrong type throws a SerializationException with a clear message.
• HttpAdapter: HTTP error statuses reach onError. Non-2xx responses
  skipped the error interceptors, so 5xx/429 responses were never retried and
  never served from stale cache.
• DioAdapter/RetrofitAdapter: ETag revalidation works. A 304 Not Modified was thrown as a ServerException instead of serving the cached
  data.
• Builder timeouts are applied. withConnectTimeout, withReceiveTimeout,
  and withSendTimeout were stored but ignored. HttpAdapter also ignored
  the per-request timeouts of ApiRequest.
• Stale-while-revalidate is implemented. enableStaleWhileRevalidate was
  accepted but had no effect.
• Retries run in a single loop. Retries used to nest recursively, which
  logged the final error once per attempt and over-counted
  RetryMetrics.successfulRetries.
• Retrofit retries. Retries created a new Dio per attempt that was never
  closed, dropped timeouts and response settings, and stopped after the
  first failed retry. They now reuse the adapter's client.
• Retrofit request changes. Changes interceptors make to the path,
  method, query, body, timeouts, or removed headers now reach the request.
• HttpAdapter URLs. Absolute URLs in ApiRequest.path are supported,
  and query strings in the path are merged with queryParameters instead of
  being dropped.
• HttpAdapter bodies. JSON bodies are sent as application/json; they
  were previously sent as text/plain unless a Content-Type was given. Map
  bodies with application/x-www-form-urlencoded are sent as form fields. A
  body that cannot be JSON-encoded throws SerializationException, and is no
  longer retried as a NetworkException.
• HttpAdapter responses respect the response charset and no longer fail
  on invalid UTF-8.
• Logger masking. maskedKeys now masks body fields (at any depth,
  including JSON strings) and response headers, as documented. Before, only
  request headers were masked, and passwords in bodies were logged in
  plain text. Keys are matched case-insensitively on both sides.
• The default LoggerConfig.maskedKeys also mask proxy-authorization,
  cookie, set-cookie, x-api-key, api_key, access_token,
  refresh_token, and client_secret.
• The logger never fails a request. Bodies that are not JSON-encodable
  used to throw in JSON and curl output.
• The logger printed error durations as 0:00:00.123000ms, and
  requestFilter did not apply to errors.
• RetryConfig.calculateDelay overflowed to 0 for large attempt numbers,
  and allowed negative custom delays.
• ApiRequest.hashCode differed for equal requests with headers.
• CacheInterceptor threw on very large max-age values, cached no-cache
  responses without revalidation, did not renew entries after a 304, and
  did not count a miss when revalidating.
• CacheConfig.keyBuilder now receives the query string, so requests that
  differ only by query parameters no longer share a cache entry.
• DioAdapter omits null query parameters, like HttpAdapter.
• MemoryCacheStore threw for maxEntries <= 0.
• CacheKeyGenerator.generate threw for query values that are not
  JSON-encodable.

New

• Request cancellation: ApiCancelToken and ApiRequest.cancelToken.
  Cancelling aborts in-flight requests on every adapter, interrupts pending
  retry delays, and throws CancellationException, which is never retried.
  One token can cancel many requests. With RetrofitAdapter, Dio's
  CancelToken now also interrupts api_plus retry delays.
• HttpAdapter and DioAdapter accept connectTimeout, receiveTimeout,
  and sendTimeout.
• Accurate HttpAdapter timeouts: connect, send, and receive timeouts
  now apply to the matching phase of the request, like Dio. The receive
  timeout is an idle timeout between response chunks. Requests are aborted
  when a timeout fires.
• MemoryCacheStore.evictionCount, and CacheMetrics.evictions now counts
  MemoryCacheStore LRU evictions.
• onResponse interceptors now see error responses on every adapter (they
  already did with HttpAdapter).

Behavior changes

• The minimum SDK is now Dart 3.4. http ^1.6.0 already required it, so the
  previous >=3.1.0 constraint could not be satisfied on older SDKs.
• Non-ApiException errors thrown by interceptors are propagated unchanged.
  They are no longer wrapped in NetworkException and retried.
• HttpAdapter returns non-JSON content types (e.g. text/plain) as
  String instead of attempting to JSON-decode them, matching Dio.
• RetryConfig.onRetry is called before the delay, as documented.
• ServerException messages are the same on every adapter:
  Server returned <status>: <reason>.

Documentation and tooling

• README rewritten: pipeline semantics, typed responses, timeouts, cache keys
  and user-specific data, platform setup (macOS entitlements, Android
  permission), limitations, and migration notes.
• Adapter integration tests against a real local server, plus regression
  tests for the fixes above.
• CI tests on the real minimum SDK (3.4.0), checks the lowest dependency
  versions, and runs on develop.
• Removed unused dev dependencies (mocktail, fake_async).