CalcBaseFee calculates the basefee of the header.

VerifyEip1559Header verifies some header attributes which were changed in EIP-1559, - gas limit check - basefee check.

VerifyForkHashes verifies that blocks conforming to network hard-forks do have the correct hashes, to avoid clients going off on different chains.

VerifyGaslimit verifies the header gas limit according increase/decrease in relation to the parent gas limit.