NodeInvoker typedef
Invokes action on a node and returns its response payload.
The seam between this proxy and the transport. In production it is backed by
OmnyHub's NodeGateway.request; in tests it is a direct call into a
StoreRpcServer, which is what makes the whole federation testable without
binding a socket.
Implementation
typedef NodeInvoker =
Future<Map<String, dynamic>> Function(
String action,
Map<String, dynamic> payload,
);