NewBranch parent is branch that has the header previous to this header.

NewRepository returns a new Repository.

ErrHeaderNotAvailable means the header has been pruned and is not available.

ErrInvalidTarget means the target bits are not correct for the difficulty algorithm.

ErrNotEnoughWork means the target bits are correct but the hash doesn't meet the target.

ErrUnknownHeader means the header isn't known and doesn't link to any known header.

ErrWrongChain means the header is known to belong to another chain (BTC, BCH, ...).

Repository is used for managing header data.