React Native and Objective C delegates

I am quite new to react native and and the bridging mechanism with native code, especially when the framework has delegates. Assume I am trying to bridge the following framework:

@protocol BRPtouchNetworkDelegate;

@class PLNetworkModule;

@interface BRPtouchNetworkManager : NSObject <NSNetServiceBrowserDelegate,NSNetServiceDelegate>


@property(retain, nonatomic) NSMutableArray* registeredPrinterNames;
@property(assign, nonatomic) BOOL isEnableIPv6Search;


- (int)startSearch: (int)searchTime;
- (NSArray*)getPrinterNetInfo;

- (BOOL)setPrinterNames:(NSArray*)strPrinterNames;
- (BOOL)setPrinterName:(NSString*)strPrinterName;

- (id)initWithPrinterNames:(NSArray*)strPrinterNames;
- (id)initWithPrinterName:(NSString*)strPrinterName;

@property (nonatomic, assign) id <BRPtouchNetworkDelegate> delegate;

@end

@protocol BRPtouchNetworkDelegate <NSObject>

-(void) didFinishSearch:(id)sender;

@end


The following is the bridge module I implemented:

RCTBRPtouchNetworkManager.h

#import <React/RCTBridgeModule.h>
#import <BRPtouchPrinterKit/BRPtouchPrinterKit.h>

@interface RCTBRPtouchNetworkManager : NSObject <RCTBridgeModule, BRPtouchNetworkDelegate>
@end


RCTBRPtouchNetworkManager.m

#import "RCTBRPtouchNetworkManager.h"
#import <BRPtouchPrinterKit/BRPtouchPrinterKit.h>
#import <React/RCTLog.h>

@implementation RCTBRPtouchNetworkManager {
BRPtouchNetworkManager *_networkManager;
}

RCT_EXPORT_MODULE();

RCT_EXPORT_METHOD(addEvent:(NSString *)name location:(NSString *)location)
{
RCTLogInfo(@"Pretending to create an event %@ at %@", name, location); //a dummy method to test the bridge
}

RCT_EXPORT_METHOD(startSearchWithTimeout:(int)time) {
RCTLogInfo(@"Bridge started search with time %d", time);

_networkManager = [[BRPtouchNetworkManager alloc] init];
_networkManager.delegate = self; //I'm setting delegate here
_networkManager.isEnableIPv6Search = NO;
NSString * path = [[NSBundle mainBundle] pathForResource:@"PrinterList" ofType:@"plist"];
if( path )
{
NSDictionary *printerDict = [NSDictionary dictionaryWithContentsOfFile:path];
NSArray *printerList = [[NSArray alloc] initWithArray:printerDict.allKeys];
[_networkManager setPrinterNames:printerList];
} else {
RCTLogInfo(@"PrinterList path not found");
}

// Start printer search
[_networkManager startSearch: 5.0];

}

- (void)didFinishSearch:(id)sender {
NSLog(@"didFinishedSearch"); //this delegate method is not called
}

@end


I can easily call the dummy method and see the results in the logs. However, the delegate method didFinishSearch() is never called. I call this from javascript as follows:

componentDidMount() {
let networkManager = NativeModules.BRPtouchNetworkManager;
networkManager.startSearchWithTimeout(5.0);
}


I there something I am missing? Am I implementing delegate properly? Is this kind of functionality even possible (can't seem to not since the delegate method was used by iOS community for a long time). Your help is much appreciated.

EDIT

I found that adding the following to my bridge manager file made the delegate to fire (thanks to this post)

- (dispatch_queue_t)methodQueue
{
return dispatch_get_main_queue();
}


However, even though this solves the problem, I'd like a more technical understanding on what is going on here since I can't seem to exactly grasp it. Thank you

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