code: public TransactionFlow<T,R> peek(Consumer<R> c){
  		 return map (in-> { c.accept(in); return in;});
  	}
docs: Consume current data within the context of a transaction.
  An exception in the consumption process will cause Rollback
  Transaction will be completed once the entire flow has completed
  <pre>
  {code
  Integer result = TransactionFlow.of(transactionTemplate, this::load)
  .consume(this::save)
  .execute(10)
  .get();
  }
  </pre>
  
  @param c Consumer to accept current data
  @return TransactionFlow