Switch to ConcurrentDictionary for the api client cache
Switch to ConcurrentDictionary for the api client cache

pwz3n0/VisualStudio,bradthurber/VisualStudio,AmadeusW/VisualStudio,luizbon/VisualStudio,github/VisualStudio,github/VisualStudio,yovannyr/VisualStudio,HeadhunterXamd/VisualStudio,YOTOV-LIMITED/VisualStudio,GuilhermeSa/VisualStudio,github/VisualStudio,naveensrinivasan/VisualStudio,amytruong/VisualStudio