Use locking to make the pooled StringBuilder safer - even though we'd have safely exchanged references before, the builder itself might not have been thread-safe without any memory barriers.
Use locking to make the pooled StringBuilder safer - even though we'd have
safely exchanged references before, the builder itself might not have been
thread-safe without any memory barriers.

We'll see what this does to performance...

jskeet/nodatime,malcolmr/nodatime,zaccharles/nodatime,zaccharles/nodatime,malcolmr/nodatime,nodatime/nodatime,malcolmr/nodatime,BenJenkinson/nodatime,nodatime/nodatime,zaccharles/nodatime,BenJenkinson/nodatime,zaccharles/nodatime,jskeet/nodatime,zaccharles/nodatime,zaccharles/nodatime,malcolmr/nodatime