registerFallback method
Registers a fallback method on this server.
A server may have any number of fallback methods. When a request comes in that doesn't match any named methods, each fallback is tried in order. A fallback can pass on handling a request by throwing a RpcException.methodNotFound exception.
callback
can return either a JSON-serializable object or a Future that
completes to a JSON-serializable object. Any errors in callback
will be
reported to the client as JSON-RPC 2.0 errors. callback
may send custom
errors by throwing an RpcException.
Implementation
void registerFallback(Function(Parameters parameters) callback) {
_fallbacks.add(callback);
}