code: protected void pushContext(Context c) {
  		Stack<Context> stack = threadSafeContextStack.get();
  		if (stack == null) {
  			stack = new Stack<Context>();
  			stack.push(c);
  			threadSafeContextStack.set(stack);
  		} else {
  			threadSafeContextStack.get().push(c);
  		}
  	}
docs: Push a new write context onto the stack.