private static string GetAccessKey(AwsSettings awsSettings)
{
var key = awsSettings.AccessKey;
if (!string.IsNullOrWhiteSpace(key)) return key;
#if NET45
key = System.Configuration.ConfigurationManager.AppSettings["AWSAccessKey"];
if (!string.IsNullOrWhiteSpace(key)) return key;
#endif
return Environment.GetEnvironmentVariable("AWS_ACCESS_KEY_ID");
}