Condition key for The URL, e-mail address, or ARN from a Subscribe
            request or a previously confirmed subscription. Use with string
            conditions to restrict access to specific endpoints (e.g.,
            *@mycompany.com).
            
This condition key may only be used with ConditionFactory..::..StringComparisonType enum.
 Declaration Syntax
 Declaration Syntax| C# | 
public const string SNS_ENDPOINT_CONDITION_KEY