[feat] Added metric into tqdm bar.

nanovllm/utils/observer.py

@@ -0,0 +1,17 @@
+class Observer():
+    ttft_start = 0
+    tpot_start = 0
+
+    ttft = 0
+    tpot = 0
+
+    @classmethod
+    def reset_ttft(cls):
+        cls.ttft_start = 0
+
+    @classmethod
+    def complete_reset(cls):
+        cls.ttft_start = 0
+        cls.tpot_start = 0
+        cls.ttft = 0
+        cls.tpot = 0