```release-note:new-resource
aws_ec2_transit_gateway_multicast_domain
```

```release-note:new-resource
aws_ec2_transit_gateway_multicast_domain_association
```

```release-note:new-resource
aws_ec2_transit_gateway_multicast_group_member
```

```release-note:new-resource
aws_ec2_transit_gateway_multicast_group_source
```

```release-note:new-data-source
aws_ec2_transit_gateway_multicast_domain
```

```release-note:enhancement
resource/aws_ec2_transit_gateway: Add `multicast_support` argument
```

```release-note:enhancement
data-source/aws_ec2_transit_gateway: Add `multicast_support` attribute
```