casync: reuse requests session in RemoteChunkReader (#25045)

system/hardware/tici/casync.py

@@ -55,6 +55,7 @@ class RemoteChunkReader(ChunkReader):
   def __init__(self, url: str) -> None:
     super().__init__()
     self.url = url
+    self.session = requests.Session()
 
   def read(self, chunk: Chunk) -> bytes:
     sha_hex = chunk.sha.hex()
@@ -62,7 +63,7 @@ class RemoteChunkReader(ChunkReader):
 
     for i in range(CHUNK_DOWNLOAD_RETRIES):
       try:
-        resp = requests.get(url, timeout=CHUNK_DOWNLOAD_TIMEOUT)
+        resp = self.session.get(url, timeout=CHUNK_DOWNLOAD_TIMEOUT)
         break
       except Exception:
         if i == CHUNK_DOWNLOAD_RETRIES - 1: