minio/docs/debugging/xl-meta
Klaus Post 518612492c
xl-meta: Add header titles (#13880)
Add type for headers and create custom marshal to make 
it easier to read. Group headers and metadata.

Restore functionality that will read `xl.meta` in the current dir with no params.

Before:
```
{
  "Headers": [
    [
      "8M04bTiYRDmEMQGeAsk1yg==",
      1639150471630100400,
      "rLD1Rw==",
      1,
      6
    ],
  ],
    "Versions": [
    {
      "Type": 1,
      "V2Obj": {
        "CSumAlgo": 1,
        "DDir": "oC1Xpg4tRfW03g8o8w7Bzg==",
        "EcAlgo": 1,
        "EcBSize": 1048576,
        "EcDist": [
          7,
          8,
          1,
          2,
          3,
          4,
          5,
          6
        ],
        "EcIndex": 1,
        "EcM": 4,
        "EcN": 4,
        "ID": "8M04bTiYRDmEMQGeAsk1yg==",
        "MTime": 1639150471630100400,
        "MetaSys": {
          "x-minio-internal-inline-data": "dHJ1ZQ=="
        },
        "MetaUsr": {
          "content-type": "application/octet-stream",
          "etag": "b8252c86fad2d8937300aa92b467a3aa"
        },
        "PartASizes": [
          1000
        ],
        "PartETags": null,
        "PartNums": [
          1
        ],
        "PartSizes": [
          1000
        ],
        "Size": 1000
      }
    }
  ]
}
```

After:
```
{
  "Versions": [
    {
      "Header": {
        "Flags": 6,
        "ModTime": "2021-12-10T16:34:31.6301004+01:00",
        "Signature": "acb0f547",
        "Type": 1,
        "VersionID": "f0cd386d389844398431019e02c935ca"
      },
      "Idx": 0,
      "Metadata": {
        "Type": 1,
        "V2Obj": {
          "CSumAlgo": 1,
          "DDir": "oC1Xpg4tRfW03g8o8w7Bzg==",
          "EcAlgo": 1,
          "EcBSize": 1048576,
          "EcDist": [
            7,
            8,
            1,
            2,
            3,
            4,
            5,
            6
          ],
          "EcIndex": 1,
          "EcM": 4,
          "EcN": 4,
          "ID": "8M04bTiYRDmEMQGeAsk1yg==",
          "MTime": 1639150471630100400,
          "MetaSys": {
            "x-minio-internal-inline-data": "dHJ1ZQ=="
          },
          "MetaUsr": {
            "content-type": "application/octet-stream",
            "etag": "b8252c86fad2d8937300aa92b467a3aa"
          },
          "PartASizes": [
            1000
          ],
          "PartETags": null,
          "PartNums": [
            1
          ],
          "PartSizes": [
            1000
          ],
          "Size": 1000
        }
      }
    }
  ]
}
```
2021-12-10 15:03:25 -08:00
..
main.go xl-meta: Add header titles (#13880) 2021-12-10 15:03:25 -08:00