expose Headers::new and Extensions::new

Author: jbr

Diff for: src/extensions.rs

@@ -21,7 +21,7 @@ pub struct Extensions {
 impl Extensions {
     /// Create an empty `Extensions`.
     #[inline]
-    pub(crate) fn new() -> Self {
+    pub fn new() -> Self {
         Self { map: None }
     }
 

Diff for: src/headers/headers.rs

@@ -34,7 +34,7 @@ pub struct Headers {
 
 impl Headers {
     /// Create a new instance.
-    pub(crate) fn new() -> Self {
+    pub fn new() -> Self {
         Self {
             headers: HashMap::new(),
         }