gistfile1.txt

// assumed
let FindPackages(_,_,_,_) = [| "package" |]
type Source = { IsNuget: bool; Url: string }
let DefaultNugetSource = { IsNuget = true; Url = "http://nuget.org" }

//-------------------------------
// using parallel merged asyncSeq's

let SearchPackagesByName(sources, search) = 
    let sources = [ yield! sources; yield  DefaultNugetSource ]    
    [ for source in sources ->
        asyncSeq { if source.IsNuget then 
                     for p in FindPackages(None, source.Url, search, 1000) do
                        yield p } ]
    |> AsyncSeq.mergeAll