bpo-32410: Avoid blocking on file IO in sendfile fallback code (GH-7172) (#7182)
(cherry picked from commit 7165754b6b5f3b7c07050d921fa1c58bba5f0ff1)
Co-authored-by: Yury Selivanov <yury@magic.io>
diff --git a/Lib/asyncio/constants.py b/Lib/asyncio/constants.py
index 739b0a7..d7ba496 100644
--- a/Lib/asyncio/constants.py
+++ b/Lib/asyncio/constants.py
@@ -14,6 +14,10 @@
# Number of seconds to wait for SSL handshake to complete
SSL_HANDSHAKE_TIMEOUT = 10.0
+# Used in sendfile fallback code. We use fallback for platforms
+# that don't support sendfile, or for TLS connections.
+SENDFILE_FALLBACK_READBUFFER_SIZE = 1024 * 256
+
# The enum should be here to break circular dependencies between
# base_events and sslproto
class _SendfileMode(enum.Enum):