SharePoint REST and C# Sample to UPDATE LIST ITEM

Somehow I am not able to find a very basic sample of SharePoint REST.

My requirements are

1. C# (no javascript)

2. REST (no CSOM)

3. Update List Item (not just list title)

I did search and find many many resources

http://social.msdn.microsoft.com/Forums/en-US/b1d103a4-71c9-423c-8403-e3dbf519c089/updating-list-items-in-a-document-library-using-sharepoint-2013-rest-api-c?forum=sharepointdevelopment

But they don't contain the answer because 

1. they just change the list title and not the item.

2. use java script

3. Use some very generic tutorial about REST without the specifics of how to update a list item using REST and C#.

I think this is what I am looking for

url: http://site url/_api/web/lists/GetByTitle(‘Test')/items(item id)
method: POST
body: { '__metadata': { 'type': 'SP.Data.TestListItem' }, 'Title': 'TestUpdated'}
headers:
    Authorization: "Bearer " + accessToken
     X-RequestDigest: form digest value“IF-MATCH”: etag or “*”
    “X-HTTP-Method”:”MERGE”,
    accept: "application/json;odata=verbose"
    content-type: "application/json;odata=verbose"
    content-length:length of post body

But I don't know how to convert this into a C# Console Application. (No JavaScript, No Auto-hosted).