crypto on Nostr: 所以用户名是独一无二的吗？

{ "id": "d5409acdeee204b4aac039e38d3d3d27834c4ecd8fa91ba000d462de94688e93", "pubkey": "561cc2f9e234f58ba42ed63a6b8de99d5d5caf1adf4582b9ac7893afd81d9479", "created_at": 1675296699, "kind": 1, "tags": [], "content": "所以用户名是独一无二的吗？", "sig": "ee65def259651e4f73cc83293ac1a76c274e3d69699eb5c981a5dc0026fa79984c7174ffd79c2c58540a25a47e3adfa09bf0ae8933f2499d16b87f008e73f690" }