+---------+             +===========+             +-----------+
| Client  |             # Cache     #             | Server    |
| asks    |             # remembers #             | owns data |
+---------+             +===========+             +-----------+
     :                        :                         :
     :-- get ---------------->:                         :
     :<. miss ................:                         :
     :-- fetch ---------------------------------------->:
     :<. data ..........................................:
     :-- put ---------------->:                         :
     :                        :                         :
