This structure can be used to store a statically bound reference &'static T in a
safe wrapper that also implements Send and Sync. These traits are implemented
because the content cannot be recovered after the construction, and also because
the pointer has a static lifetime.
A packed array is an array of cell (u64) with a fixed length and a varying bits
length (byte size) that allows it to store multiple values in the same cell.
An iterator to unpack aligned values in from an u64 iterator.
This iterator only requires an byte size and will output every
value found in each cell. What means “aligned” is that value
cannot be defined on two different cells, if there is remaining
space in cells, it is ignored.