/// <summary>
/// Gets an existing http client.
/// </summary>
/// <param name="username">Account username.</param>
/// <returns>Http client.</returns>
public HttpClient GetClient(string username, string host)
{
var client = AllClients
.Except(Clients.Select(i => i.Value))
.FirstOrDefault();
if (client == null)
{
client = CreateClient(host);
AllClients.Add(client);
Clients.Add(username, client);
}
return(client);
}