Number of NAKs this source transport has shed and sent an NCF with the reason code set to "shed".

When a source transport's retransmit rate limiter and retransmit queue are both at maximum, it responds to a NAK by sending an "NCF shed", and does not retransmit. The receiver transport should wait, then send another NAK. If this count is high, one or more crybaby receiver transports may be clogging the source transport's retransmit queue. This method returns a value from the nth set of statistics encapsulated within this object.