AmazonKeyspacesFixedRateThrottler: Detected a synchronous API call on a driver thread, failing because this can cause deadlocks.

Class `AmazonKeyspacesFixedRateThrottler` doesn't seem to work. The error is,

```
2024-04-23 01:08:22,107 ERROR [main] log.GlueLogger (GlueLogger.scala:error(7)): ERROR: Detected connectivity issue. Check the reference conf file/Glue connection for the source, the job is aborted java.io.IOException: Failed to open native connection to Cassandra at Profile based config at CassandraConnector.conf :: Error instantiating class com.aws.ssa.keyspaces.throttler.AmazonKeyspacesFixedRateThrottler (specified by advanced.throttler.class): Detected a synchronous API call on a driver thread, failing because this can cause deadlocks.
```

Here's the configuration block I'm using,

```
advanced.throttler {
class = com.aws.ssa.keyspaces.throttler.AmazonKeyspacesFixedRateThrottler
max-requests-per-second = 100
number-of-hosts = 3
register-timeout = 15 seconds
}
```

Start by reproducing the failure with the AmazonKeyspacesFixedRateThrottler configuration shown in the issue and trace where the throttler is instantiated. Determine why synchronous API calls occur on the driver thread; done means the configuration initializes without the reported deadlock-prevention error.

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