An `Address` value is used as an interface between vectors and indices. The index maps keys of various types to address, which is then used to get a value from the vector. Here is a brief summary of what we assume (and don't assume) about addresses: - Address is `int64` (although we might need to generalize this in the future) - Different data sources can use different addressing schemes (as long as both index and vector use the same scheme) - Addresses don't have to be continuous (e.g. if the source is partitioned, it can use 32bit partition index + 32bit offset in the partition) - In the in-memory representation, address is just index into an array - In the BigDeedle representation, address is abstracted and comes with `AddressOperations` that specifies how to use it (tests use linear offset and partitioned representation) [category:Vectors and indices]

public static class Addressing