UIApplicationDelegateProxyType.m

#import <UIKit/UIKit.h>

@interface ApplicationDelegateProxyType ()

@property (nonnull, nonatomic) NSArray<id <UIApplicationDelegate>> *objects;

@end

@implementation ApplicationDelegateProxyType

static NSArray<id <UIApplicationDelegate>> *(^_provider)(void) = nil;

- (instancetype)init {
    _objects = [_provider() copy];
    return self;
}

+ (void)setDelegateProvider:(NSArray<id <UIApplicationDelegate>> * (^)(void))provider {
    _provider = provider;
}

- (BOOL)respondsToSelector:(SEL)aSelector {
    for (id <UIApplicationDelegate> delegate in self.objects) {
        if ([delegate respondsToSelector:aSelector]) {
            return YES;
        }
    }
    return NO;
}

- (void)forwardInvocation:(NSInvocation *)invocation {
    SEL sel = invocation.selector;
    for (id <UIApplicationDelegate> delegate in self.objects) {
        if ([delegate respondsToSelector:sel]) {
            [invocation invokeWithTarget:delegate];
        }
    }
}

- (NSMethodSignature *)methodSignatureForSelector:(SEL)sel {
    for (NSObject *delegate in self.objects) {
        if ([delegate respondsToSelector:sel]) {
            return [delegate methodSignatureForSelector:sel];
        }
    }
    return nil;
}

@end
    
// main.swift
    
ApplicationDelegateProxyType.setDelegateProvider { () -> [UIApplicationDelegate]? in
    return [
        MainDelegate(),
        AnalyticsDelegate()
    ]
}

UIApplicationMain(
    CommandLine.argc,
    UnsafeMutableRawPointer(CommandLine.unsafeArgv)
        .bindMemory(
            to: UnsafeMutablePointer<Int8>.self,
            capacity: Int(CommandLine.argc)),
    NSStringFromClass(UIApplication.self),
    NSStringFromClass(ApplicationDelegateProxyType.self)
)