v2-12-homework

---

2-12-homework - 2024-06-13

Features

• support echo command - (053d0e0) - luffy
• support hmget command - (01ea458) - luffy
• support command sadd and sismember - (45fbf81) - luffy

Refactoring

• remove NullArray and NullBulkString - (c590d45) - luffy