set the timeout in a cb_flag to allow other exit reasons

Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>
exit reason id, when multiple exit reasons are possible + doc of the public struct

Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>
rename timeout to flag

Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>
add 2 other exit path for network latency

Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>