registerMethod method
Registers a method named name on this server.
callback can take either zero or one arguments. If it takes zero, any
requests for that method that include parameters will be rejected. If it
takes one, it will be passed a Parameters object.
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.
Implementation
void registerMethod(String name, Function callback) {
if (_methods.containsKey(name)) {
throw ArgumentError('There\'s already a method named "$name".');
}
_methods[name] = callback;
}