Running benchmarks against Memcached

[yatsukhnenko]

See https://github.com/cachewerk/relay-core/issues/1204

> @php benchmarks/run '--workers' '1' 'BenchmarkGet.php'
Setting up on AMD Ryzen 7 4700U with Radeon Graphics (8 cores/8 threads x86_64)
Using PHP 8.3.26 (OPcache: Off, Xdebug: Off, New Relic: Off)
Connected to Redis (8.2.2) at tcp://127.0.0.1:6379
Connected to Memcached (1.6.39) at tcp://127.0.0.1:11211

 GET  Executing 5 iterations (1 warmup) for 1.00s seconds

+--------------+--------+---------+---------+---------+-------------+---------+--------+--------+
| Client       | Memory | Network | Workers | IOPS    | IOPS/Worker | rstdev  | Change | Factor |
+--------------+--------+---------+---------+---------+-------------+---------+--------+--------+
| Predis       | 1.42mb | 20.72mb |       1 |  54.13K |      54.13K |  ±6.09% |  0.00% |  1.00x |
| PhpRedis     | 1.43mb | 25.24mb |       1 |  66.51K |      66.51K |  ±1.97% | 22.87% |  1.23x |
| RelayNoCache | 1.43mb | 26.75mb |       1 |  70.50K |      70.50K |  ±1.41% | 30.23% |  1.30x |
| Memcached    | 1.43mb |  5.91mb |       1 | 128.22K |     128.22K |  ±2.49% |   137% |  2.37x |
| Relay        | 1.43mb |    181b |       1 |   2.76M |       2.76M | ±24.81% | 5,003% |  51.0x |
+--------------+--------+---------+---------+---------+-------------+---------+--------+--------+