(feat): Unpack extensions into complex function types #8

The more in-depth we use extensions, the more likely is is that we need custom extensions. New `UnpackExtensions` function in the high package makes this easy. Low level models have been updated to support feature fully and docs added in README and examples as well.

Signed-off-by: Dave Shanley <dave@quobix.com>

datamodel/low/v2/swagger_test.go

@@ -60,6 +60,7 @@ func TestCreateDocument(t *testing.T) {
     assert.Equal(t, true, doc.FindExtension("x-pet").Value)
     assert.Equal(t, true, doc.FindExtension("X-Pet").Value)
     assert.NotNil(t, doc.GetExternalDocs())
+    assert.Len(t, doc.GetExtensions(), 1)
 }
 
 func TestCreateDocument_Info(t *testing.T) {