buildHandshakePayload property
Called right after the socket connects, to build the payload emitted
as the "handshake" event (see SmartApiSocket.init's
handshakeEvent) — e.g. {"id": userId, "device_token": fcmToken}.
Return an empty map to skip emitting a handshake for this connection (useful before the user is logged in). Async is supported, so you can await a push-notification token or a value from local storage here.
Implementation
static FutureOr<Map<String, dynamic>> Function()? buildHandshakePayload;