the rate at which new tokens are deposited at the bucket. Actual rate might vary slightly due to rounding errors. In general, the lower the number, the lower the error.
the maximal number of tokens that the bucket may hold. Unless overdraft is allowed, this is also the maximal amount that a single withdrawl may request.
the number of tokens initially in the bucket. If unspecified, the bucket starts out as completely full.
initialize a throttler for use.