CGSize maximumTextViewSize = CGSizeMake(320- 30 ,FLT_MAX);
// 게다가 좌우 여백을 줘야 그나마 비슷하게 구해진다!

CGSize expectedLabelSize =[strToCursor  sizeWithFont:self.currentTextView.font
						        constrainedToSize:maximumTextViewSize
							lineBreakMode:UILineBreakModeWordWrap];
									    	
DLog(@"expectedLabelSize height [%f]", expectedLabelSize.height); //sometimes wrong height !!