https://travis-ci.org/github/bitcoin/bitcoin/jobs/679885530#L8791
#ifndef BITCOIN_INTERFACES_CHAIN_H
#define BITCOIN_INTERFACES_CHAIN_H
#include <optional.h>               
#include <primitives/transaction.h> 
#include <util/settings.h>          
#include <functional>
#include <memory>
#include <stddef.h>
#include <stdint.h>
#include <string>
#include <vector>
class ArgsManager;
class CBlock;
class CFeeRate;
class CRPCCommand;
class CScheduler;
class Coin;
class uint256;
enum class MemPoolRemovalReason;
enum class RBFTransactionState;
struct bilingual_str;
struct CBlockLocator;
struct FeeCalculation;
struct NodeContext;
namespace interfaces {
class Handler;