Distinguishing Between Streaming and Non-Streaming Events in TaskManager

Currently, when using the OnTaskCreated, OnMessageReceived, and OnTaskUpdated events of TaskManager, it's impossible to tell whether those were triggered by the streaming request or a non-streaming one. This is important for scenarios when users want to handle those by delegating the calls to the corresponding streaming or non-streaming APIs of the underlying LLM/Agent/SDK/Service.