Function shumate_data_source_start_request 

pub unsafe extern "C" fn shumate_data_source_start_request(
    self_: *mut ShumateDataSource,
    x: c_int,
    y: c_int,
    zoom_level: c_int,
    cancellable: *mut GCancellable,
) -> *mut ShumateDataSourceRequest

Available on crate feature v1_1 only.