Revert "新增了 Transactions 命名空间及其相关的代码文件。"

This reverts commit f33cb7df9fb93d9fe910c083441f43e39249e885.
Revert "Revert "新增了 Transactions 命名空间及其相关的代码文件。""

This reverts commit 503e499e76dc142c3f4e7d079090b47d50b5501f.
Merge remote-tracking branch 'origin/master'