Encoding:
    SILC_ASN1_ANY(buffer)
    SILC_ASN1_ANY_T(opts, tag, buffer)

    Decoding:
    SILC_ASN1_ANY(&buffer)
    SILC_ASN1_ANY_T(opts, tag, buffer)

    Macro used to encode or decode another ASN.1 node.  The buffer type
    is SilcBuffer.  This macro can be used for example to split large
    tree into multiple nodes, and then decoding the nodes separately from
    the buffers.

    The `opts' is SilcAsn1Options.  The `tag' is a tag number.

    // Encode node of two boolean values
    silc_asn1_encode(asn1, node,
                     SILC_ASN1_BOOLEAN(val1),
                     SILC_ASN1_BOOLEAN(val2),
                     SILC_ASN1_END);

    // Encode tree with the node
    silc_asn1_encode(asn1, tree,
                     SILC_ASN1_SEQUENCE_T(SILC_ASN1_PRIVATE, 101),
                       SILC_ASN1_ANY(node),
                       SILC_ASN1_BOOLEAN(boolval),
                     SILC_ASN1_END, SILC_ASN1_END);