public async Task Exists()
{
// Check if a package exists.
NuGetClient client = new NuGetClient("https://api.nuget.org/v3/index.json");
if (!await client.ExistsAsync("newtonsoft.json"))
{
Console.WriteLine("Package 'newtonsoft.json' does not exist!");
}
var packageVersion = NuGetVersion.Parse("12.0.1");
if (!await client.ExistsAsync("newtonsoft.json", packageVersion))
{
Console.WriteLine("Package 'newtonsoft.json' version '12.0.1' does not exist!");
}
}