4.0.0

[4.0.0] - 2021-02-22

Starting with this version, the API documentation for the latest release is viewable at https://launchdarkly.github.io/dotnet-eventsource.

The 4.x major version of LaunchDarkly.EventSource will be used in the upcoming major version releases of LaunchDarkly's .NET-based SDKs. This release streamlines the API, updates platform compatibility, and improves performance.

Added:

• EventSource.Restart: this method allows the caller to trigger a connection restart even if there was not an error on the stream.
• MessageEvent.Name: previously, the event name was only available as a property of MessageReceivedEventArgs.
• ConfigurationBuilder.DefaultEncoding: sets the character encoding to use for parsing the stream data if the server did not specify an encoding in its Content-Type.
• ConfigurationBuilder.PreferDataAsUtf8Bytes: an optional mode in which EventSource will read the data: property of events as a raw UTF-8 byte array (assuming the stream encoding is UTF-8) to avoid unnecessarily allocating a UTF-16 string. This is meant as an optimization for applications that will be processing the data with a UTF-8-based API such as System.Text.Json.
• Simple EventSource(Uri) constructor for cases where you do not need any other configuration options.
• Standard .NET XML documentation of all public types and methods is now produced in the build.
• The release now publishes a Source Link package.

Changed:

• The minimum .NET Standard compatibility version is now 2.0.
• The minimum .NET Framework compatibility version is now 4.5.2.
• Logging now works through the new LaunchDarkly.Logging facade which is used by LaunchDarkly .NET-based SDKs, instead of Common.Logging.
• ConfigurationBuilder methods no longer throw any exceptions, except for one case: passing null for the stream URI. In all cases where a property has a maximum and/or minimum value, if you try to set a value outside that range it will simply be changed to the closest valid value. If two properties do not make sense to use together (such as a non-null HttpClient and a non-null HttpMessageHandler), one will simply override the other as described in the API documentation.
• ConfigurationBuilder.DelayRetryDuration is named to InitialRetryDelay, which more accurately describes its meaning.
• ConfigurationBuilder.MessageHandler is renamed to HttpMessageHandler, since that's the name of its type (also, "message" has other meanings in this API).
• The type of Configuration.HttpContentFactory is now simply Func<HttpContent> rather than using a custom delegate type.
• If you pass a Dictionary of headers to ConfigurationBuilder.RequestHeaders, it will now be copied. Previously the configuration retained a reference to the original Dictionary, which could cause problems if it was later modified.
• EventSource now implements the stream read timeout in a way that uses the task scheduler more efficiently. Previously, it executed an additional task for each read with Task.Delay; now, it uses a timed cancellation token.
• Exception messages have been rewritten for clarity and style.

Fixed:

• ConfigurationBuilder.BackoffResetThreshold had no effect; the default value was being used regardless of what you set it to.
• When reading the SSE stream, EventSource was using a case-insensitive comparison to recognize field names like event and data. The SSE specification states that field name "must be compared literally, with no case folding performed," so a field name like EVENT is invalid.

Removed:

• Removed all types and methods that were marked as deprecated/obsolete in the last 3.x version.
• Configuration no longer has a public constructor. Instances must now be created with Configuration.Builder.
• The helper class ExponentialBackoffWithDecorrelation is no longer public.