code: func completenessEstimate(token int64) float64 {
  	tokenRange := float64(*endToken) - float64(*startToken)
  	tokensProcessed := float64(token) - float64(*startToken)
  
  	return tokensProcessed / tokenRange
  }
docs: // completenessEstimate estimates completess of this process (as a number between 0 and 1)
  // by inspecting a cassandra token. The data is ordered by token, so assuming a uniform distribution
  // across the token space, we can estimate process.
  // the token space is -9,223,372,036,854,775,808 through 9,223,372,036,854,775,807
  // so for example, if we're working on token 3007409301797035962 then we're about 0.66 complete