⚡ improve traffic_state_of function by simplifying the if-else condit…

…ion cost (#115)

…
traffic_state_of is a critical function that is called many times. any
improvement there result in noticeable performance bump.

CHANGES.rst

@@ -1,3 +1,8 @@
+2.7.908 (2024-05-16)
+====================
+
+- Improve ``traffic_state_of`` function to improve the overall performance in a highly concurrent context.
+
 2.7.907 (2024-05-05)
 ====================
 

src/urllib3/_version.py

@@ -1,4 +1,4 @@
 # This file is protected via CODEOWNERS
 from __future__ import annotations
 
-__version__ = "2.7.907"
+__version__ = "2.7.908"

src/urllib3/connectionpool.py

@@ -120,6 +120,10 @@ def close(self) -> None:
         Close all pooled connections and disable the pool.
         """
 
+    @property
+    def is_idle(self) -> bool:
+        raise NotImplementedError
+
 
 # This is taken from http://hg.python.org/cpython/file/7aaba721ebc0/Lib/socket.py#l252
 _blocking_errnos = {errno.EAGAIN, errno.EWOULDBLOCK}

src/urllib3/util/_async/traffic_police.py

@@ -64,10 +64,10 @@ def __init__(self, maxsize: int | None = None, concurrency: bool = False):
 
         self.__ctx_cursor: contextvars.ContextVar[
             tuple[int, T] | None
-        ] = contextvars.ContextVar("cursor")
+        ] = contextvars.ContextVar("cursor", default=None)
         self.__ctx_wait_clock: contextvars.ContextVar[
             float | None
-        ] = contextvars.ContextVar("wait_clock")
+        ] = contextvars.ContextVar("wait_clock", default=None)
 
     @property
     def _cursor(self) -> tuple[int, T] | None:

src/urllib3/util/traffic_police.py

@@ -49,15 +49,12 @@ class AtomicTraffic(TrafficPoliceFine, queue.Empty):
 
 def traffic_state_of(manageable_traffic: ManageableTraffic) -> TrafficState:
     if (
-        hasattr(manageable_traffic, "is_saturated")
+        getattr(manageable_traffic, "is_saturated", None)
         and manageable_traffic.sock is not None  # type: ignore[union-attr]
-        and manageable_traffic.is_saturated
     ):
         return TrafficState.SATURATED
-    elif hasattr(manageable_traffic, "is_idle"):
-        return TrafficState.IDLE if manageable_traffic.is_idle else TrafficState.USED
     else:
-        return TrafficState.IDLE
+        return TrafficState.IDLE if manageable_traffic.is_idle else TrafficState.USED
 
 
 class TrafficPolice(typing.Generic[T]):