Tile availability and content availability are written to separate buffers

[sanjeetsuhag]

{
  "bufferViews": [
    {
      "buffer": 0,
      "byteLength": 683,
      "byteOffset": 0
    },
    {
      "buffer": 1,
      "byteLength": 683,
      "byteOffset": 0
    }
  ],
  "buffers": [
    {
      "byteLength": 688
    },
    {
      "byteLength": 688,
      "uri": "../availability/7_0_0.bin"
    }
  ],
  "childSubtreeAvailability": {
    "constant": 0
  },
  "contentAvailability": {
    "bufferView": 1
  },
  "tileAvailability": {
    "bufferView": 0
  }
}

The tiler is writing the tileAvailability and contentAvailability to separate buffers even when they have identical data - as they most often will, with CDB datasets.