Float64LeadingBitMask contains bits that store the leading bit count.

Float64NewLeadingTrailingBit indicates that encoding uses new leading/trailing bit counts.

Float64NonIdenticalBit indicates that the value is not identical to the previous value.

Float64SigBitMask contains bits that store the trailing bit count.

Float64SigBitsCount the of bits used by Float64SigBitMask, same as the number of bits to shift Float64LeadingBitMask to get its value.