我正在尝试按map的两个值对map进行排序。首先是时间戳，然后是随机数。换句话说，我需要能够首先迭代并打印具有最小时间戳的map，然后是nonce值。像这样:"tx1":Transaction{Value:10,Nonce:1,Timestamp:1563543005},"tx2":Transaction{Value:20,Nonce:2,Timestamp:1563543005},"tx6":Transaction{Value:60,Nonce:2,Timestamp:1563543005},"tx5":Transaction{Value:50,Nonce:4,Timestamp:1