Many coders cause significant unnecessary allocations

Many coders (BigEndian*, Map, Iterable, Instant) use DataInputStream to read longs/ints/shorts.  Internally each DataInputStream allocates ~200 bytes of buffers when instantiated.  This means every long, int, short, etc decoded allocates over 200 bytes.

We should eliminate all uses of DataInputStream in hot-paths and replace it with something more efficient.