Append a full element to a buffer
@param buffer = is the target buffer
@param type = is the HiBON type
@param key = is the member key
@param x = is the value of the element
@param index = is offset index in side the buffer and index with be progressed
Append a full element to a buffer @param buffer = is the target buffer @param type = is the HiBON type @param key = is the member key @param x = is the value of the element @param index = is offset index in side the buffer and index with be progressed