• Aggregation thread is now a background thread

• Move W3C methods from Web SDK

• Flatten IExtension and Unknown ITelemetry implementations for Rich Payload Event Source consumption
• Fix: Start/StopOperation with W3C distributed tracing enabled does not track telemetry
• Fix: Do not run metric aggregation on a thread pool thread

Important: The 2.9.0-beta2 has a known issue - Installing this package will create ApplicationInsights.config file, but it'll not set it to be copied to output directory. Users are advised to set this file to 'Copy if newer' so that build output will have the ApplicationInsights.config file.
This is expected to be fixed in next beta.

• Remove unused reference to System.Web.Extensions
• PageViewTelemetry now supports ISupportMetrics
• Fixed a bug in TelemetryContext which prevented rawobject store to be not available in all sinks.
• Fixed a bug where TelemetryContext would have missing values on secondary sinks
• Fixed race condition in BroadcastProcessor which caused it to drop TelemetryItems
• Custom Telemetry Item that implements ITelemetry is no longer dropped, bur rather serialized as EventTelemetry and handled by the channels accordingly
• IExtension is now serialized into the Properties and Metrics

Perf Improvements.

• Improved Perf of ITelemetry JsonSerialization
• Added new method on TelemetryClient to initialize just instrumentation. This is to be used by autocollectors to avoid calling TelemetryInitializers twice.
• RequestTelemetry modified to lazily instantiate ConcurrentDictionary for Properties
• RequestTelemetry modified to not service public fields with data class to avoid converting between types.
• Dependency Telemetry modified to lazily instantiate ConcurrentDictionary for Properties
• Avoid string allocations in Metrics hot path

Patch release addressing perf regression.

• New API to store/retrieve any raw objects on TelemetryContext to enable AutoCollectors to pass additional information for use by TelemetryInitializers.
• Perf Improvements
  #927
  #930
  #934
• Fix: Response code shouldn't be overwritten to 200 if not set

• TelemetryProcessors (sampling, autocollectedmetricaggregator), TelemetryChannel (ServerTelemetryChannel) added automatically to the default ApplicationInsights.config are moved under the default telemetry sink.
  If you are upgrading, and have added/modified TelemetryProcessors/TelemetryChannel, make sure to copy them to the default sink section.

• Add a new distict properties collection, GlobalProperties, on TelemetryContext, and obsolete the Properties on TelemetryContext.
• Added support for strongly typed extensibility for Telemetry types using IExtension.
• [New method SerializeData(ISerializationWriter writer) defined in ITelemetry. All existing types implement this method to emit information about it's fields to channels who can serialize this data]
  (continuation of #871)
• Allow to track PageViewPerformance data type.
• Added method ExceptionDetailsInfoList on ExceptionTelemetry class that gives control to user to update exception
  message and exception type of underlying System.Exception object that user wants to send to telemetry. Related discussion is here.
• Added an option of creating ExceptionTelemetry object off of custom exception information rather than a System.Exception object.
• Add support for hex values in config