#import "ViewController.h"

@interface SpecialLabel:UILabel

@end

@implementation SpecialLabel

- (CGSize)sizeThatFits:(CGSize)size {

    CGSize s = [super sizeThatFits:size];

    return CGSizeMake(s.width +, s.height +);

}

@end

@interface ViewController ()

@property (weak, nonatomic) IBOutlet SpecialLabel *label;

@end

@implementation ViewController

- (IBAction)changeText {

    self.label.text = @"fsdgdssssssssssss ";

#if 1

    [[NSOperationQueue mainQueue] addOperationWithBlock:^{

        [self.label sizeToFit];

    }];

#else

    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.001 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{

         [self.label sizeToFit];

    });

#endif

}

self.label.text = @"fsdgdssssssssssss ";

[self.label sizeToFit];