AsyncOperation.h

// You need to subclass this and populate the main method
// To complete the operation call [self completeOperation]

#import <Foundation/Foundation.h>

@interface AsyncOperation : NSOperation

- (void)completeOperation;

@end

AsyncOperation.m

#import "AsyncOperation.h"

@interface AsyncOperation()
{
    BOOL _executing;
    BOOL _finished;
}

@end


@implementation AsyncOperation

#pragma mark - Init

- (instancetype)init
{
    if (self = [super init]) {
        _executing = NO;
        _finished = NO;
    }
    
    return self;
}

#pragma mark - Async Operation

- (void)start
{
    if ([self isCancelled]) {
        [self willChangeValueForKey:@"isFinished"];
        _finished = YES;
        [self didChangeValueForKey:@"isFinished"];
        return;
    }
    
    [self willChangeValueForKey:@"isExecuting"];
    [NSThread detachNewThreadSelector:@selector(main) toTarget:self withObject:nil];
    _executing = YES;
    [self didChangeValueForKey:@"isExecuting"];
}


- (void)completeOperation
{
    NSLog(@"END OF OPERATION");
    
    [self willChangeValueForKey:@"isFinished"];
    [self willChangeValueForKey:@"isExecuting"];
    _executing = NO;
    _finished = YES;
    [self didChangeValueForKey:@"isExecuting"];
    [self didChangeValueForKey:@"isFinished"];
}

- (BOOL)isConcurrent { return YES; }

- (BOOL)isFinished { return _finished; }

- (BOOL)isExecuting { return _executing; }

@end