NewHTTPClient factory function returns a new http.Client with the appropriate settings and can limit number of clients per host if the OptMaxConnPerHost option is set.

RetryPolicy wraps retryablehttp.DefaultRetryPolicy and included additional logic: - checks for specific errors that indicate a fall-back to the next download strategy - checks for http.StatusBadGateway and http.StatusServiceUnavailable which also indicate a fall-back.

PGetHTTPClient is a wrapper around http.Client that allows for limiting the number of concurrent connections per host utilizing a client pool.