! @brief Writes a BSON element with key @a name and null value */

! @param[in] j JSON value to serialize @pre j.type() == value_t::object */

! @brief Writes a BSON element with key @a name and object @a value */

! @brief Writes a BSON element with key @a name and string value @a value */

! @brief Writes a BSON element with key @a name and unsigned @a value */

! @brief destructor Destroys the JSON value and frees all allocated memory. @complexity Linear. @requirement This function helps `b