⭐ 𝗣𝗔𝗥𝗧 𝟯 — 𝗪𝗵𝗲𝗿𝗲 𝗔𝗜 𝗦𝘁𝗿𝘂𝗴𝗴𝗹𝗲𝘀 (𝗮𝗻𝗱 𝗪𝗵𝘆 𝗦𝗲𝗻𝗶𝗼𝗿 𝗘𝗻𝗴𝗶𝗻𝗲𝗲𝗿𝘀 𝗠𝗮𝘁𝘁𝗲𝗿)

𝗔𝗜 𝗮𝗰𝗰𝗲𝗹𝗲𝗿𝗮𝘁𝗲𝘀 - 𝗯𝘂𝘁 𝗶𝘁 𝗱𝗼𝗲𝘀𝗻’𝘁 𝘂𝗻𝗱𝗲𝗿𝘀𝘁𝗮𝗻𝗱 𝗽𝗿𝗼𝗱𝘂𝗰𝘁𝗶𝗼𝗻. 𝐈𝐭 𝐡𝐞𝐥𝐩𝐞𝐝 𝐚 𝐥𝐨𝐭 - 𝐛𝐮𝐭 𝐢𝐭 𝐚𝐥𝐬𝐨 𝐦𝐢𝐬𝐬𝐞𝐝 𝐭𝐡𝐢𝐧𝐠𝐬 𝐭𝐡𝐚𝐭 𝐨𝐧𝐥𝐲 𝐞𝐱𝐩𝐞𝐫𝐢𝐞𝐧𝐜𝐞 𝐜𝐚𝐭𝐜𝐡𝐞𝐬. 𝗘𝗱𝗴𝗲 𝗰𝗮𝘀𝗲𝘀 AI suggested basic heartbeat handling but missed a key nuance: stale detection must be per‑channel, not global. My initial implementation cleared all stale flags when any message arrived. That keeps the UI green - but it hides channel‑specific failures. Bitfinex channels can fail independently, so each subscription needs its own stale timer. That’s the kind of detail you only learn by shipping real systems.