SilcAttributesPayload
    silc_attribute_payload_alloc(SilcAttribute attribute,
                                 SilcAttributeFlags flags,
                                 void *object,
                                 SilcUInt32 object_size);

    Allocates and encodes the attribute indicated by `attribute' and
    returns pointer to the attribute.

    The `object' must always be the same data type as defined with
    SilcAttribute (see the comments) for all attributes.