Issue trying to implement codeAction/resolve in omnisharp-roslyn

I am sure I am missing something (maybe I just don't understand dynamic registration) but I am not able to implement codeAction/resolve in omnisharp-roslyn.

The first thing that makes me confused is why omnisharp-roslyn reports no codeActionProvider as response to initialize, as evidenced by this log:

[Trace - 01:25:24 PM] Received response 'initialize - (19)' in 768ms.
Result: {
  "serverInfo": {
    "version": "1.0.0+c802f8ea91d8ab24d07564c917d0bab8326b3f71",
    "name": "OmniSharp"
  },
  "capabilities": {
    "workspace": {
      "fileOperations": {
      },
      "workspaceFolders": {
        "changeNotifications": true,
        "supported": true
      }
    },
    "implementationProvider": {
    },
    "experimental": {
    },
    "executeCommandProvider": {
      "commands": [
        "omnisharp/executeCodeAction",
        "omnisharp/executeCodeAction"
      ]
    },
    "documentOnTypeFormattingProvider": {
      "moreTriggerCharacter": [
        "}",
        ")"
      ],
      "firstTriggerCharacter": ";"
    },
    "codeLensProvider": {
      "resolveProvider": true
    },
    "workspaceSymbolProvider": {
    },
    "documentSymbolProvider": {
    },
    "referencesProvider": {
    },
    "definitionProvider": {
    },
    "signatureHelpProvider": {
      "triggerCharacters": [
        ".",
        "?",
        "["
      ]
    },
    "completionProvider": {
      "triggerCharacters": [
        "."
      ]
    },
    "hoverProvider": {
    },
    "textDocumentSync": {
      "save": {
        "includeText": true
      },
      "change": 1,
      "openClose": true
    }
  }

Then I tried to implement codeAction/resolve support here:

• https://github.com/razzmatazz/omnisharp-roslyn/commit/04ed94b43198d24c72fa58e66154c247e6e02cbe

But I really not sure if I am dabbling in the right direction, do we really need separate OmniSharpCodeActionResolveHandler or not -- and can I use data on CodeAction? -- it seems to be serialized properly though so I assume it is.

Start with the initialize response in the issue and the linked commit 04ed94b43198d24c72fa58e66154c247e6e02cbe. Inspect how codeActionProvider, CodeAction data, and codeAction/resolve are represented, then verify that the server advertises the capability and handles resolution correctly.