C# - RestSharp Sample API Code

We develop a business application called Triumph ERP, which is written using DataFlex. We have recently added some supplier based REST API resources, e.g.
* Get Suppliers
* Get Supplier Transactions
* Post Supplier Invoice

We would like to get some simple C# - RestSharp example code written. The code needs to be clear, understandable and well written, with a working application to go with it.

The application and examples need to cover the following calls…

Authentication - request a session id
http://localhost:80/TriumphWS/6.3/rest/sessionid

Get all supplier/creditor accounts
http://localhost:80/TriumphWS/6.3/rest/creditors

Get the name, Id and ABN for a given creditor
http://localhost:80/TriumphWS/6.3/rest/creditors/CITMAN?fields=Name|CRMACC%23|ABN_No

Get list of creditor invoices after a starting point, i.e. transaction id
http://localhost:80/TriumphWS/6.3/rest/creditortransactions?Start=21

Get the header details for a given creditor invoice
http://localhost:80/TriumphWS/6.3/rest/creditortransactions/21

Get all the line details for a given creditor invoice
http://localhost:80/TriumphWS/6.3/rest/creditortransactions/21/lines

Post a creditor’s batch invoice
http://localhost:80/TriumphWS/6.3/rest/creditorbatchinvoice

We will provide the real test server address/links to the person who get’s the job. Results can be displayed in a simple text box.

Attached is a technical document that goes into more detail. Note that in terms of coding, we only want the above calls.