EntityFrameworkCore 当中使用了 using 创建事务是否需要显式 Rollback

using var context = new BloggingContext();
using var transaction = context.Database.BeginTransaction();

try
{
    context.Blogs.Add(new Blog { Url = "http://blogs.msdn.com/dotnet" });
    context.SaveChanges();

    context.Blogs.Add(new Blog { Url = "http://blogs.msdn.com/visualstudio" });
    context.SaveChanges();

    var blogs = context.Blogs
        .OrderBy(b => b.Url)
        .ToList();

    // Commit transaction if all commands succeed, transaction will auto-rollback
    // when disposed if either commands fails
    transaction.Commit();
}
catch (Exception)
{
    // TODO: Handle failure
}

    // .method private hidebysig instance void
      // Dispose(
        // bool disposing
      // ) cil managed
    private void Dispose(bool disposing)
    // .maxstack 8
    // 
    // IL_0000: ldarg.1      // disposing
    // IL_0001: brfalse.s    IL_0018
    // IL_0003: ldarg.0      // this
    // IL_0004: ldfld        class System.Data.SqlClient.SqlInternalConnection System.Data.SqlClient.SqlInternalTransaction::_innerConnection
    // IL_0009: brfalse.s    IL_0018
    // IL_000b: ldarg.0      // this
    // IL_000c: ldc.i4.1
    // IL_000d: stfld        bool System.Data.SqlClient.SqlInternalTransaction::_disposing
    // IL_0012: ldarg.0      // this
    // IL_0013: call         instance void System.Data.SqlClient.SqlInternalTransaction::Rollback()
    // IL_0018: ret
    // 
    {
      if (!disposing || this._innerConnection == null)
        return;
      this._disposing = true;
      this.Rollback();
    }