Resolve "Subquery support"

Closes #43 (closed)

src/query/mod.rs

@@ -244,7 +244,7 @@ impl From<(u64, Unit)> for Duration {
 
 /// Specify time offset for the queries
 #[derive(Debug, Clone, Copy)]
-pub struct Offset(i64, Unit);
+pub struct Offset(pub i64, pub Unit);
 
 impl Display for Offset {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {