{[mem3, shard_cache, eviction], [
    {type, counter},
    {desc, <<"number of shard cache evictions">>}
]}.
{[mem3, shard_cache, hit], [
    {type, counter},
    {desc, <<"number of shard cache hits">>}
]}.
{[mem3, shard_cache, miss], [
    {type, counter},
    {desc, <<"number of shard cache misses">>}
]}.
