Method `calcMaxBufferCount` only calls one time?

[wang9262]

If the memory warning is not trigged, the method calcMaxBufferCount only called in imageChanged. Imagine this situation：

YYFrameImage *images = [[YYFrameImage alloc] initWithImagePaths:imagePaths oneFrameDuration:0.05 loopCount:10];
// 1
YYAnimatedImageView *indefiniteAnimatedView = [[YYAnimatedImageView alloc] initWithImage:images]; 
// 2
indefiniteAnimatedView.maxBufferSize = 5 * 1024 * 1024;

//1、This will make the method imageChanged and calcMaxBufferCount called, and the maxBufferSize is 0, So the _maxBufferCount is dynamically caculated.

// 2、After the imageChanged method called, setting the maxBufferSize does nothing, and the _maxBufferCount doesn't change, which means setting max buffer size after setting image will has no effect.

Maybe move the caculate method to startAnimating method is better?