Assume two different threads feeding a single channel with a sequence of transactions. If the transactions are just put in to the channel without using channel grab() the result would be that the sequence between two threads will be mixed producing unexpected results. Grab() method is used to request for exclusive access to the channel once the grab is activated no other thread can put an object in to the channel. Once the channel is loaded with the sequence of transaction object ungrab() should be used to release the channel for other threads. Is_grabbed () function can be used to know if the channel is grabbed.Lock () method can be used to lock the channel producer (put ) or channel consumer (get ). Unlock () can be initiated to remove the lock(). Status of the lock can be got using is_locked() method. These methods are useful to control channel from a different location say different block.