Aws-sdk-php: Retry on TooManyRequestsException

[teohhanhui]

Is this related to a problem?

Some actions in Cognito return the TooManyRequestsException error.

Feature description

RetryMiddleware should handle the TooManyRequestsException error.

Describe alternatives you've considered

• It's impossible to pass custom $additionalRetryConfig through the AwsClient constructor $args.
• It's impossible to modify the $additionalRetryConfig on the registered RetryMiddleware ("retry").
• It's impossible to retrieve the registered "retry" middleware.
• It's impossible to replace the registered "retry" middleware by the same name.
• It's impossible to access the AwsClient constructor $args in order to correctly configure a replacement RetryMiddleware.

Additional context

• https://docs.aws.amazon.com/cognito-user-identity-pools/latest/APIReference/API_ListUsers.html#API_ListUsers_Errors
• https://docs.aws.amazon.com/cognito/latest/developerguide/limits.html#limits-soft
• https://github.com/aws/aws-sdk-php/blob/3.100.7/src/ClientResolver.php#L390-L399
• https://github.com/aws/aws-sdk-php/pull/1672

[howardlopez]

Thanks for bringing this up. TooManyRequestsException is being added in #1827.