debug function
Implementation
void debug(List<int> payload) {
print('version: ${payload.getRange(0, 4)}');
print('depth: ${payload.getRange(4, 5)}');
print('parent fingerprint: ${payload.getRange(5, 9)}');
print('childNumber: ${payload.getRange(9, 13)}');
print('chaincode: ${payload.getRange(13, 46)}');
print('key: ${payload.getRange(46, 78)}');
print('checksum: ${payload.getRange(78, 82)}');
}