Used internally by client-side code. To initialize the client context for development with the Project Server CSOM, use ProjectContext.
Assembly: Microsoft.ProjectServer.Client (in Microsoft.ProjectServer.Client.dll)
You should use the ProjectContext class for development with the CSOM in Microsoft Project Server 2013. Because the object inherits from the SharePoint ClientContext object, it maintains the context for development with both the Project Server CSOM and the SharePoint CSOM.
An advantage of the ProjectContext class is that it includes the WaitForQueue method. If you used the ProjectServer class, you would have to develop your own routines to wait for a queue job to complete.