text: // The MIT License (MIT)
  //
  // Copyright (c) 2015-2016 forkingdog ( https://github.com/forkingdog )
  //
  // Permission is hereby granted, free of charge, to any person obtaining a copy
  // of this software and associated documentation files (the "Software"), to deal
  // in the Software without restriction, including without limitation the rights
  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  // copies of the Software, and to permit persons to whom the Software is
  // furnished to do so, subject to the following conditions:
  //
  // The above copyright notice and this permission notice shall be included in all
  // copies or substantial portions of the Software.
  //
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  // SOFTWARE.
  
  #import <UIKit/UIKit.h>
  
  @interface FDKeyedHeightCache : NSObject
  
  //heightForKey
  - (BOOL)existsHeightForKey:(id<NSCopying>)key;
  //存储height key
  - (void)cacheHeight:(CGFloat)height byKey:(id<NSCopying>)key;
  //获取height
  - (CGFloat)heightForKey:(id<NSCopying>)key;
  
  // Invalidation
  - (void)invalidateHeightForKey:(id<NSCopying>)key;
  //缓存的高度
  - (void)invalidateAllHeightCache;
  @end
  
  @interface UITableView (FDKeyedHeightCache)
  
  /// Height cache by key. Generally, you don't need to use it directly.
  @property (nonatomic, strong, readonly) FDKeyedHeightCache *fd_keyedHeightCache;
  @end
  