Add SOCKS5 dialer

See: https://github.com/valyala/fasthttp/issues/161

fasthttpproxy/socks5.go

@@ -0,0 +1,25 @@
+package fasthttpproxy
+
+import (
+	"net"
+
+	"github.com/valyala/fasthttp"
+	"golang.org/x/net/proxy"
+)
+
+// FasthttpSocksDialer returns a fasthttp.DialFunc that dials using
+// the provided SOCKS5 proxy.
+//
+// Example usage:
+// c := &fasthttp.Client{
+//   Dial: fasthttpproxy.FasthttpSocksDialer("localhost:9050"),
+// }
+func FasthttpSocksDialer(proxyAddr string) fasthttp.DialFunc {
+	return func(addr string) (net.Conn, error) {
+		dialer, err := proxy.SOCKS5("tcp", proxyAddr, nil, proxy.Direct)
+		if err != nil {
+			return nil, err
+		}
+		return dialer.Dial("tcp", addr)
+	}
+}