hk_request_to_write_steps.m

- (void)requestToWriteDataWithFinishBlock:(void (^)(NSError *error))finishBlock
{
    // write permission
    NSArray *writeTypes = @[
                            [HKObjectType quantityTypeForIdentifier:HKQuantityTypeIdentifierStepCount]
                            ];
    
    [self.healthStore requestAuthorizationToShareTypes:[NSSet setWithArray:writeTypes]
                                             readTypes:nil
                                            completion:^(BOOL success, NSError * _Nullable error) {
                                                
                                                dispatch_sync(dispatch_get_main_queue(), ^{
                                                    
                                                    if (error) {
                                                        finishBlock(error);
                                                    } else {
                                                        finishBlock(nil);
                                                    }
                                                });
                                            }];
}