Lock the session map until after DialOr.
Lock the session map until after DialOr.

In case two requests come in simultaneously with the same session ID,
make one block until DialOr is finished.

arlolra/meek,scucoco/meek,wyuelin/mymeek,scucoco/meek,projectarkc/meek,gorshell/forkmeek,arlolra/meek,Yawning/meek,gorshell/forkmeek,gorshell/forkmeek,Yawning/meek,infinity0/meek,arlolra/meek,projectarkc/meek,Yawning/meek,wyuelin/mymeek,scucoco/meek,projectarkc/meek,projectarkc/meek,wyuelin/mymeek,Yawning/meek,infinity0/meek,infinity0/meek,infinity0/meek,projectarkc/meek,infinity0/meek,gorshell/forkmeek,wyuelin/mymeek