Type of backoff values.

Logarithm of the maximum allowed value for wait.

create creates a backoff value. upper_wait_log, lower_wait_log override the logarithmic upper and lower bound on the number of spins executed by once.

default is equivalent to create ().

once b executes one random wait and returns a new backoff with logarithm of the current maximum value incremented unless it is already at upper_wait_log of b.

Note that this uses the default Stdlib Random per-domain generator.

reset b returns a backoff equivalent to b except with current value set to the lower_wait_log of b.

get_wait_log b returns logarithm of the maximum value of wait for next once.