[mem] Introduce PoolStats dataclass; unify pool metrics and token_usage (#22554)

test/registered/unit/managers/test_scheduler_pause_generation.py

@@ -9,6 +9,7 @@ maybe_stub_sgl_kernel()
 
 from sglang.srt.managers.io_struct import PauseGenerationReqInput
 from sglang.srt.managers.scheduler import Scheduler
+from sglang.srt.managers.scheduler_runtime_checker_mixin import PoolStats
 
 register_cpu_ci(est_time=10, suite="stage-a-test-cpu")
 
@@ -33,7 +34,14 @@ class TestSchedulerPauseGeneration(unittest.TestCase):
         scheduler.token_to_kv_pool_allocator = MagicMock()
         scheduler.token_to_kv_pool_allocator.available_size.return_value = 1000
         scheduler.max_total_num_tokens = 1000
-        scheduler._get_token_info = MagicMock(return_value=(0, 0, 1000, 0))
+        scheduler._get_token_info = MagicMock(
+            return_value=PoolStats(
+                full_num_used=0,
+                full_token_usage=0,
+                full_available_size=1000,
+                full_evictable_size=0,
+            )
+        )
         return scheduler
 
     def test_inplace_only_sets_flag(self):