Writer

called when reader/writer can become no more available for some reason

capture object, and after this we can or use one (markUsed will be called) or abandon (markFree)

if this object is expired and should be deleted from queue (for example: when reader is belong to select group and some other action in this select group was performed)

Called when we can't use captured function (i.e. get function but ).

Called when we submitt to task executor readFunction and now is safe to make exprire all other readers/writers in the same select group