t.Errorf("newFileConn: udp conn type mismatch: %T", c)
	} else {
		testIsUDPAddr(t, "LocalAddr", c.LocalAddr())
		testIsUDPAddr(t, "RemoteAddr", c.RemoteAddr())
	}
}

func testIsTCPAddr(t *testing.T, method string, addr Addr) {
	if _, ok := addr.(*TCPAddr); !ok {
		t.Errorf("%s: returned address is not a *TCPAddr: %T", method, addr)
	}
}

func testIsUDPAddr(t *testing.T, method string, addr Addr) {