add support for streaming clone.
existing clone code uses pull to get changes from remote repo. is very
slow, uses lots of memory and cpu.
new clone code has server write file data straight to client, client
writes file data straight to disk. memory and cpu used are very low,
clone is much faster over lan.
new client can still clone with pull, can still clone from older servers.
new server can still serve older clients.
#!/bin/sh
hg init a
cd a
echo a > foo
hg rm foo
hg add foo
hg commit -m 1 -d "1000000 0"
hg remove
rm foo
hg remove foo
hg revert
rm foo
hg remove --after
hg commit -m 2 -d "1000000 0"
hg export 0
hg export 1
hg log -p -r 0
hg log -p -r 1
echo a > a
hg add a
hg rm a
hg rm -f a
echo b > b
hg ci -A -m 3 -d "1000001 0"
echo c >> b
hg rm b
hg rm -f b
cd ..
hg clone a b