Draft Specification for V2

• Make bit assignment customizable
  • BitLenMachineID = 63 - BitLenTime - BitLenSequence

type Settings struct {
	BitLenTime     int
	BitLenSequence int
	StartTime      time.Time
	MachineID      func() (int, error)
	CheckMachineID func(int) bool	
}

• Remove NewSonyflake
  • Use New instead

func New(st Settings) (*Sonyflake, error)
func NewSonyflake(st Settings) *Sonyflake

• NextID returns int64 instead of uint64

func (sf *Sonyflake) NextID() (int64, error)