More efficient variable-length integer keys

[dw]

The current encoding throws away a byte for every integer encoded: since only 10 values of the discriminator byte are currently used.

We could instead collapse the first byte of the integer at least partially into the discriminator, say as:

• 10==NEG_INT3 -> next 3 bytes are -65535..0xffffff
• 11==NEG_INT2 -> next 2 bytes are -256..65535
• 12==NEG_INT1 -> next byte is -0..255
• 13==INT1 -> next byte is 0..255
• 14==INT2 -> next 2 bytes are 256..65535
• 15==INT3 -> next 3 bytes are 65535..0xffffff

etc.

A separate varint encoding might still needed for e.g. allocating encoding prefixes, but there are alternative solutions for that