[Docs] Include a code example for rack-awareness

[GeoffMontee]

Starting with 1.8.0, our release of GoCQL supports rack-awareness.

We have some limited documentation about this feature here:

gocql/doc.go

Line 131 in b2d210a

// # Rack-level awareness

Perhaps we could include a more complete example in the documentation. For example:

cluster := gocql.NewCluster("192.168.1.1", "192.168.1.2", "192.168.1.3")
cluster.PoolConfig.HostSelectionPolicy = gocql.RackAwareRoundRobinPolicy("AWS_US_EAST_1", "us-east-1a")

We might also want to include a disclaimer about AWS specifically, where AZs do not have consistent names between different AWS accounts. Maybe the documentation can provide more detailed guidance about this or refer to the AWS documentation that mentions how to obtain the internal AZ IDs.

[GeoffMontee]

We might also want to include a disclaimer about AWS specifically, where AZs do not have consistent names between different AWS accounts. Maybe the documentation can provide more detailed guidance about this or refer to the AWS documentation that mentions how to obtain the internal AZ IDs.

Here's the corresponding AWS Documentation page: Availability Zone IDs for your AWS resources