Add support of proxy protocol

internal/proxyprotocol/conn.go

@@ -0,0 +1,25 @@
+package proxyprotocol
+
+import "github.com/pires/go-proxyproto"
+
+type connWrapper struct {
+	*proxyproto.Conn
+}
+
+func (c connWrapper) CloseRead() error {
+	tcpConn, ok := c.TCPConn()
+	if !ok {
+		panic("we support only tcp connections")
+	}
+
+	return tcpConn.CloseRead()
+}
+
+func (c connWrapper) CloseWrite() error {
+	tcpConn, ok := c.TCPConn()
+	if !ok {
+		panic("we support only tcp connections")
+	}
+
+	return tcpConn.CloseWrite()
+}