if set _shouldCacheLayoutFrames YES , DTCoreTextLayoutFrame will be cached. so when numberOfLines or lineBreakMode or truncationString changed,  call suggestedFrameSizeToFitEntireStringConstraintedToWidth always return old size.
if set _shouldCacheLayoutFrames YES , DTCoreTextLayoutFrame will be cached.
so when numberOfLines or lineBreakMode or truncationString changed,  call suggestedFrameSizeToFitEntireStringConstraintedToWidth always return old size.

Cocoanetics/DTCoreText,Cocoanetics/DTCoreText,Cocoanetics/DTCoreText