ApproxLen would indicate the total number of UIDs in the pack.

Decode decodes the UidPack back into the list of uids.

Encode takes in a list of uids and a block size.

ExactLen would calculate the total number of UIDs.

SeekCurrent to Seek() a Uid using it as offset, not as part of the results.

SeekStart is used with Seek() to search relative to the Uid, returning it in the results.

Decoder is used to read a pb.UidPack object back into a list of UIDs.

Encoder is used to convert a list of UIDs into a pb.UidPack object.