Lex Runtime V2 > Structures > HeartbeatEvent HeartbeatEvent¶ Structure Class¶ HeartbeatEvent dataclass ¶ Event that Amazon Lex V2 sends to indicate that the stream is still open between the client application and Amazon Lex V2 Attributes¶ event_id class-attribute instance-attribute ¶ event_id: str | None = None A unique identifier of the event sent by Amazon Lex V2. The identifier is in the form RESPONSE-N, where N is a number starting with one and incremented for each event sent by Amazon Lex V2 in the current session.