public async Task disassociateAndDeleteDhcpOptionSet(string vpcid)
{
DescribeVpcsResponse response = await _ec2Client.DescribeVpcsAsync(new DescribeVpcsRequest {
VpcIds = new List<string>{ vpcid }
});
string dhcpOptionsId = response.Vpcs[0].DhcpOptionsId;
await _ec2Client.AssociateDhcpOptionsAsync(new AssociateDhcpOptionsRequest {
VpcId = vpcid,
DhcpOptionsId = "default"
});
await _ec2Client.DeleteDhcpOptionsAsync(new DeleteDhcpOptionsRequest{DhcpOptionsId = dhcpOptionsId});
}