Nim ORC example benchmark

[alexeypetrushin]

In the ORC example benchmark from the [Post about 
ORC](https://nim-lang.org/blog/2020/12/08/introducing-orc.html) the request 
doesn't use sessions.

I wonder how this example would look like, when request would need a) create 
sessions on demand b) Read/write to sessions made of complex GC data structures 
with refs and objects?

The code:
    
    
    import asynchttpserver, asyncdispatch, strutils, json, tables, streams
    
    # about 135 MB of live data:
    var sessions: Table[string, JsonNode]
    for i in 0 ..< 10:
      sessions[$i] = parseJson(newFileStream("1.json", fmRead), "1.json")
    
    var served = 0
    
    var server = newAsyncHttpServer()
    proc cb(req: Request) {.async.} =
      inc served
      await req.respond(Http200, "Hello World")
      if served mod 10 == 0:
        when not defined(memForSpeed):
          GC_fullCollect()
    
    waitFor server.serve(Port(8080), cb)
    
    
    Run