Make request.Request smaller (#3351)

* Make request.Request smaller

This makes the request struct smaller and removes the pointer to the do
boolean (tri-bool) as size == 0 will indicate if we have cached it.

Family can be a int8 because it only carries 3 values, Size itself is
just a uint16 under the covers.

This is a more comprehensive fix than #3292

Closes #3292

Signed-off-by: Miek Gieben <miek@miek.nl>

* cache: fix test

this now needs a valid response writter

Signed-off-by: Miek Gieben <miek@miek.nl>

request/request_test.go

@@ -13,7 +13,7 @@ func TestRequestDo(t *testing.T) {
 	st := testRequest()
 
 	st.Do()
-	if st.do == nil {
+	if !st.do {
 		t.Errorf("Expected st.do to be set")
 	}
 }