code: func (b *Driver) SetRotationRate(speed uint8) {
  	b.packetChannel <- b.craftPacket([]uint8{speed}, 0x02, 0x03)
  }
docs: // SetRotationRate allows you to control the rotation rate that Sphero will use to meet new
  // heading commands. A value of 255 jumps to the maximum (currently 400 degrees/sec).
  // A value of zero doesn't make much sense so it's interpreted as 1, the minimum.