bson_append_document_begin()
Synopsis
bool
bson_append_document_begin (bson_t     *bson,
                            const char *key,
                            int         key_length,
                            bson_t     *child);Description
The bson_append_document_begin() function shall begin appending a sub-document to bson. Use child to add fields to the sub-document. When completed, call bson_append_document_end() to complete the element.
Returns
true if the operation was applied successfully, otherwise false and bson should be discarded.