def describe_upload_buffer(GatewayARN=None):
    """
    Returns information about the upload buffer of a gateway. This operation is supported for the stored volume, cached volume and tape gateway architectures.
    The response includes disk IDs that are configured as upload buffer space, and it includes the amount of upload buffer space allocated and used.
    See also: AWS API Documentation
    
    Examples
    Returns information about the upload buffer of a gateway including disk IDs and the amount of upload buffer space allocated/used.
    Expected Output:
    Returns information about the upload buffer of a gateway including disk IDs and the amount of upload buffer space allocated and used.
    Expected Output:
    
    :example: response = client.describe_upload_buffer(
        GatewayARN='string'
    )
    
    
    :type GatewayARN: string
    :param GatewayARN: [REQUIRED]
            The Amazon Resource Name (ARN) of the gateway. Use the ListGateways operation to return a list of gateways for your account and region.
            

    :rtype: dict
    :return: {
        'GatewayARN': 'string',
        'DiskIds': [
            'string',
        ],
        'UploadBufferUsedInBytes': 123,
        'UploadBufferAllocatedInBytes': 123
    }
    
    
    """
    pass
