ProofOfWork
/// Block header information pertaining to the proof of work
#[derive(Clone, Debug, PartialEq)]
pub struct ProofOfWork {
/// Total accumulated difficulty since genesis block
pub total_difficulty: Difficulty,
/// Difficulty scaling factor between the different proofs of work
pub scaling_difficulty: u64,
/// Nonce increment used to mine this block.
pub nonce: u64,
/// Proof of work data.
pub proof: Proof,
}