public ApnsServiceBuilder withErrorDetectionThreadFactory(ThreadFactory threadFactory) {
        this.errorDetectionThreadFactory = threadFactory;
        return this;
    }
Provide a custom source for threads used for monitoring connections.

This setting is desired when the application must obtain threads from a
controlled environment Google App Engine. 
@param threadFactory
           thread factory to use for error detection
@return  this
src/main/java/com/notnoop/apns/ApnsServiceBuilder.java