Determines the number of bytes that would be required to store @value
with g_variant_store().
If @value has a fixed-sized type then this function always returned
that fixed size.
In the case that @value is already in serialised form or the size has
already been calculated (ie: this function has been called before)
then this function is O(1). Otherwise, the size is calculated, an
operation which is approximately O(n) in the number of values
involved.
Determines the number of bytes that would be required to store @value with g_variant_store().
If @value has a fixed-sized type then this function always returned that fixed size.
In the case that @value is already in serialised form or the size has already been calculated (ie: this function has been called before) then this function is O(1). Otherwise, the size is calculated, an operation which is approximately O(n) in the number of values involved.
Return: the serialised size of @value