lfs: avoid quadratic performance in processing server responses
This is also adapted from the Facebook repo[1]. Unlike there, we were already
reading the download stream in chunks and immediately writing it to disk, so we
basically avoided the problem on download. There shouldn't be a lot of data to
read on upload, but it's better to get rid of this pattern.
[1] https://github.com/facebookexperimental/eden/commit/
82df66ffe97e21f3ee73dfec093c87500fc1f6a7
Differential Revision: https://phab.mercurial-scm.org/D7882
$ hg init
$ "$PYTHON" -c 'open("a", "wb").write(b"confuse str.splitlines\nembedded\rnewline\n")'
$ hg ci -Ama -d '1 0'
adding a
$ echo clean diff >> a
$ hg ci -mb -d '2 0'
$ hg diff -r0 -r1
diff -r 107ba6f817b5 -r 310ce7989cdc a
--- a/a Thu Jan 01 00:00:01 1970 +0000
+++ b/a Thu Jan 01 00:00:02 1970 +0000
@@ -1,2 +1,3 @@
confuse str.splitlines
embedded\r (no-eol) (esc)
newline
+clean diff