Configurable log redirect

gistfile1.m

//the log manager's log method. Each log channel formats its message and then sends the whole string to this method

- (void) log:(NSString*)message
{
    if (self.logSink == nil) {
        NSLog(@"%@", message);
    } else {
        [self.logSink log:message];
    }
}

//if a sink is installed and implements this protocol, it will be called instead. 
//This sink can then redirect the message to disk, a web service, console, etc.
//This sink is installed when the library is configured during app launch

@protocol KCSLogSink <NSObject>

/** Take the incoming `message` and send it somewhere; e.g. STDOUT, NSLog, or a custom logger.
 
 @see +[KinveyKit configureLoggingWithNetworkEnabled:debugEnabled:traceEnabled:warningEnabled:errorEnabled:]
 @param message the KinveyKit log message
 @since 1.14.0
 */
- (void) log:(NSString*)message;
@end

// example implementation
@interface TestFlightLogger : NSObject <KCSLogSink>
@end
@implementation TestFlightLogger

- (void)log:(NSString *)message
{
    TFLog(@"%@", message);
}
@end