Fixed (kind of) the tests. Updated metric semantics.

Change-Id: I77730a956cac23d687bde15097c53ed66b614c45
Performance optimization.

Change-Id: I391dd1bd91f9fd4e97dcb8d94f3373c1cc1daacc
First step in yet another approach...

Change-Id: Ie64a759e47f11c79f8a14c58cf185435ba12d48d
expvar support.

Change-Id: I21fdb258111430030fde64ccd30e23d82bad7107