description

# ServiceExtensionHandler typedef Null safety

Future<ServiceExtensionResponse> ServiceExtensionHandler (

1. String method,
2. Map<String, String> parameters

)

A service protocol extension handler. Registered with registerExtension.

Must complete to a ServiceExtensionResponse. `method` is the method name of the service protocol request, and `parameters` is a map holding the parameters to the service protocol request.

NOTE: all parameter names and values are encoded as strings.

## Implementation

    typedef Future<ServiceExtensionResponse> ServiceExtensionHandler(
        String method, Map<String, String> parameters);