This fixes a theoretical issue with database interaction. Because the
fields in the database are signed 64-bit integers, it's theoretically
possible to overflow them if we're using unsigned 64-bit integers in the
application code.
Introduces data about bytes read and written to the connection close
payload. No changes are required in the Controller because the RPC
messages already contained the required fields. As of this commit,
bytes_up and bytes_down columns in the session_connection table are now
populated when a connection closes.
Refs: #2509
This commit introduces a new net.Conn implementation (countingConn) that
will keep track of bytes read and written for a particular client
connection. This is then implemented into the worker code using
interface composition.
Refs: #2501
Hugo Vieira