truncateToEvent is missing in the copilot-sdk #965
Description
Session.truncateToEvent is available on @github/copilot/sdk, but is missing on the CopilotSession that is exposed in the actual @github/copilot-sdk. We use this to implement forking in the current case for Copilot Chat, however its lack of availability in the real SDK is preventing us from doing the same thing in new explorations we're doing.