[3.13] gh-131325: fix sendfile fallback implementation to drain data after writing to transport (GH-131376)#131377

kumaraditya303 merged 1 commit intopython:3.13python/cpython:3.13from

miss-islington:backport-94f4d87-3.13miss-islington/cpython:backport-94f4d87-3.13Copy head branch name to clipboard