TCRACSocket with subjects

gistfile1.m

    TCRACSocket *socket = [TCRACSocket new];
    [[[socket connectToHost:@"localhost" port:1236] selectMany:^id<RACSubscribable>(id x) {
        return [x lines];
    }] 
     subscribeNext:^(id x) {
        self.outputField.stringValue = x;
     }
     error:^(NSError *error) {
         exit(0);
     }];

TCRACSocket.m

#import "TCRACSocket.h"
#import <AsyncSocket.h>

@interface TCRACSocket ()
@property(strong,readwrite) AsyncSocket *sock;
@property(strong) RACSubject *connectSubject;
@property(strong) RACSubject *linesSubject;
@end

@implementation TCRACSocket 
@synthesize sock = _sock;
@synthesize connectSubject = _connectSubject;
@synthesize linesSubject = _linesSubject;

-(id)init
{
    if (!(self = [super init]))
        return nil;
    
    _sock = [[AsyncSocket alloc] initWithDelegate:self];
    _linesSubject = [RACSubject subject];
    _connectSubject = [RACAsyncSubject subject];

    return self;
}

- (RACSubject *)connectToHost:(NSString *)host port:(int)port
{
    NSError *err = nil;
    if(![self.sock connectToHost:host onPort:port error:&err])
        [self.connectSubject sendError:err];

    return self.connectSubject;
}

- (void)onSocket:(AsyncSocket *)sock willDisconnectWithError:(NSError *)err;
{
    if (err) {
        [self.linesSubject sendError:err];
    } else {
        [self.linesSubject sendCompleted];
    }
}

- (void)onSocket:(AsyncSocket *)sock didConnectToHost:(NSString *)host port:(UInt16)port;
{
    [self.connectSubject sendNext:self];
    [self.connectSubject sendCompleted];

    [self.sock readDataToData:[AsyncSocket LFData] withTimeout:-1 tag:0];
}

- (void)onSocket:(AsyncSocket *)sock didReadData:(NSData *)data withTag:(long)tag
{
    NSString *s = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
    [self.linesSubject sendNext:s];
    [self.sock readDataToData:[AsyncSocket LFData] withTimeout:-1 tag:0];
}

- (RACSubscribable *)lines;
{
    return self.linesSubject;
}

@end