#include "tensorstore/transaction.h"
friend bool
tensorstore::Transaction::operator==(const Transaction& a,
                                     const Transaction& b);
friend bool
tensorstore::Transaction::operator!=(const Transaction& a,
                                     const Transaction& b);
friend bool tensorstore::Transaction::operator==(const Transaction& a,
                                                 no_transaction_t b);
friend bool
tensorstore::Transaction::operator==(no_transaction_t a,
                                     const Transaction& b);
friend bool tensorstore::Transaction::operator!=(const Transaction& a,
                                                 no_transaction_t b);
friend bool
tensorstore::Transaction::operator!=(no_transaction_t a,
                                     const Transaction& b);

Checks if a and b refer to the same transaction state, or are both null.