我当前能力对AF的理解-AFURLSessionManager.h，写给我自己

@interface AFURLSessionManager : NSObject <NSURLSessionDelegate, NSURLSessionTaskDelegate, NSURLSessionDataDelegate, NSURLSessionDownloadDelegate, NSSecureCoding, NSCopying>

@property (readonly, nonatomic, strong) NSURLSession *session;

/**
 The operation queue on which delegate callbacks are run.
　　代理回调时候，delegate所在的操作队列
 */
@property (readonly, nonatomic, strong) NSOperationQueue *operationQueue;

@property (nonatomic, strong) id <AFURLResponseSerialization> responseSerializer;

@property (nonatomic, strong) AFSecurityPolicy *securityPolicy;

@property (readwrite, nonatomic, strong) AFNetworkReachabilityManager *reachabilityManager;

/**
 The data, upload, and download tasks currently run by the managed session.
 */
@property (readonly, nonatomic, strong) NSArray <NSURLSessionTask *> *tasks;

/**
 The data tasks currently run by the managed session.
 */
@property (readonly, nonatomic, strong) NSArray <NSURLSessionDataTask *> *dataTasks;

/**
 The upload tasks currently run by the managed session.
 */
@property (readonly, nonatomic, strong) NSArray <NSURLSessionUploadTask *> *uploadTasks;

/**
 The download tasks currently run by the managed session.
 */
@property (readonly, nonatomic, strong) NSArray <NSURLSessionDownloadTask *> *downloadTasks;

/**
 The dispatch queue for `completionBlock`. If `NULL` (default), the main queue is used.
 */
@property (nonatomic, strong, nullable) dispatch_queue_t completionQueue;

/**
 The dispatch group for `completionBlock`. If `NULL` (default), a private dispatch group is used.
 */
@property (nonatomic, strong, nullable) dispatch_group_t completionGroup;