Update CHANGELOG.md

CHANGELOG.md

@@ -1,3 +1,80 @@
+### 6.4.0
+- **Introduced a new configuration API replacing the builder pattern**:
+
+  ```cs
+  ConfigCatClientBuilder
+      .Initialize(SDKKEY)
+      .WithLogger(consoleLogger)
+      .WithAutoPoll()
+          .WithMaxInitWaitTimeSeconds(5)
+          .WithPollIntervalSeconds(60)
+      .Create();
+  ```
+
+  Will look like this:
+  ```cs
+  new ConfigCatClient(options =>
+  {
+      options.SdkKey = SDKKEY;
+      options.PollingMode = PollingModes.AutoPoll(TimeSpan.FromSeconds(60), TimeSpan.FromSeconds(5));
+      options.Logger = consoleLogger;
+  });
+  ```
+
+  The old API is still available it's just marked with the `  [Obsolete]` attribute.
+
+- **`GetAllValues()` and `GetAllValuesAsync()`**:  
+  These methods are now evaluating all feature flags and settings into an `IDictionary<string, object>`.
+
+- **FlagOverrides**:  
+  It's now possible to feed the SDK with local feature flag and setting values. 
+  - **Dictionary**
+    ```cs
+    var dict = new Dictionary<string, object>
+    {
+        {"enabledFeature", true},
+        {"intSetting", 5},
+    };
+
+    using var client = new ConfigCatClient(options =>
+    {
+        options.SdkKey = "localhost";
+        options.FlagOverrides = FlagOverrides.LocalDictionary(dict, 
+            OverrideBehaviour.LocalOnly);
+    });
+    ```
+  - **File**
+    ```cs
+    using var client = new ConfigCatClient(options =>
+    {
+        options.SdkKey = "localhost";
+        options.FlagOverrides = FlagOverrides.LocalFile("path/to/file", 
+            autoReload: false, 
+            overrideBehaviour: OverrideBehaviour.LocalOnly);
+    });
+    ```
+  Three behaviours available: `LocalOnly`, `LocalOverRemote`, and `RemoteOverLocal`.
+  With `LocalOnly` the SDK switches into a complete offline state, and only the override values are served.
+  `LocalOverRemote` and `RemoteOverLocal` merge the local and remote feature flag values respecting one or another in case of key duplications.
+
+- **Changes in JSON handling**:  
+  In respect of [#30](https://github.com/configcat/.net-sdk/issues/30) `System.Text.Json` is favored over `Newtonsoft.Json` in frameworks newer than `net45`. `System.Text.Json` is not available for `net45` so that target remains using `Newtonsoft.Json`.
+
+- **`net5.0` and `net6.0` target frameworks**.
+
+- **HttpTimeout configuration option**.
+
+- **Solution for** [#26](https://github.com/configcat/.net-sdk/issues/26).
+  To prevent possible deadlocks the following changes were applied:
+  - Created a synchronous extension for the existing fully async `IConfigCache`. In the future we will replace that interface with the new one (`IConfigCatCache`) that has now the sync API and inherits the async API from `IConfigCache`.  `IConfigCache` was marked with `[Obsolete]` to maintain backward compatibility. `InMemoryConfigCache` now implements both sync and async APIs through `IConfigCatCache`.
+  - Extended the config services (`AutoPoll`, `LazyLoad`, `ManualPoll`) with synchronous branches that are using the new cache's sync / async methods in respect of sync and async customer calls.
+  - Extended the `HttpConfigFetcher` with a synchronous `Fetch` that uses the `HttpClient`'s `Send()` method where it's available (`net5.0` and above). Below `net5.0` the synchronous path falls back to a functionality that queues the HTTP request to a thread pool thread and waits for its completion. This solution prevents deadlocks however, it puts more load on the thread pool.
+
+- **CI Changes**:
+  - Introduced new [GitHub actions for Linux and macOS builds](https://github.com/configcat/.net-sdk/actions/workflows/linux-macOS-CI.yml). 
+  - The [sonarcloud analysis](https://github.com/configcat/.net-sdk/actions/workflows/sonar-analysis.yml) is moved to a separate Action from the appveyor task. 
+  - Removed codecov completely, it will be replaced by the coverage data from sonarcloud.
+
 ### 6.2.1
 - Reducing the number of json deserializations between `GetValue` calls.
 ### 6.1.20