Gets a document from DynamoDB by hash-and-range primary key,
            using specified configs.
            
 Declaration Syntax
 Declaration Syntax| C# | 
public Document GetItem( Primitive hashKey, Primitive rangeKey, GetItemOperationConfig config )
 Parameters
 Parameters- hashKey (Primitive)
- Hash key element of the document.
- rangeKey (Primitive)
- Range key element of the document.
- config (GetItemOperationConfig)
- Configuration to use.
 Return Value
 Return ValueDocument from DynamoDB.