fix(client): don't truncate manually specified filenames (#59)

Author: stainless-app[bot]

field.go

@@ -46,5 +46,5 @@ type file struct {
 	contentType string
 }
 
-func (f *file) Name() string        { return f.name }
 func (f *file) ContentType() string { return f.contentType }
+func (f *file) Filename() string    { return f.name }

internal/apiform/encoder.go

@@ -315,7 +315,9 @@ func (e *encoder) newReaderTypeEncoder() encoderFunc {
 		reader := value.Convert(reflect.TypeOf((*io.Reader)(nil)).Elem()).Interface().(io.Reader)
 		filename := "anonymous_file"
 		contentType := "application/octet-stream"
-		if named, ok := reader.(interface{ Name() string }); ok {
+		if named, ok := reader.(interface{ Filename() string }); ok {
+			filename = named.Filename()
+		} else if named, ok := reader.(interface{ Name() string }); ok {
 			filename = path.Base(named.Name())
 		}
 		if typed, ok := reader.(interface{ ContentType() string }); ok {