in SocketRocket/Internal/Utilities/SRMutex.m [16:27]
SRMutex SRMutexInitRecursive(void)
{
pthread_mutex_t *mutex = malloc(sizeof(pthread_mutex_t));
pthread_mutexattr_t attributes;
pthread_mutexattr_init(&attributes);
pthread_mutexattr_settype(&attributes, PTHREAD_MUTEX_RECURSIVE);
pthread_mutex_init(mutex, &attributes);
pthread_mutexattr_destroy(&attributes);
return mutex;
}