An array that uses a seq for extra items.
Useful for lists that allocate on the stack before using heap memory.
var da: DynArray[5, int]
# The first 5 items will use the array.
for i in 0 ..< 5:
da.add i
# When the count exceeds the array length a seq is used.
for i in 5 ..< 10:
da.add i