   public init(@noescape configBlock: (DependencyContainer->()) = { _ in }) {
     configBlock(self)
   }
-  
-  // MARK: - Thread safety
   
   private func threadSafe<T>(@noescape closure: () throws -> T) rethrows -> T {
     lock.lock()

  }
  
  var definitions = [DefinitionKey : Definition]()
  let lock = NSRecursiveLock()
  
  /**

    }
  }

}

// MARK: - Resolve dependencies

extension DependencyContainer {
  
  /**
  Resolve a dependency.
