iq, jingle_ft: Simplify item counting with Iterator::count().

src/iq.rs

@@ -222,7 +222,7 @@ impl TryFrom<Element> for Iq {
                         return Err(Error::ParseError("Wrong number of children in iq element."));
                     }
                     error_payload = Some(StanzaError::try_from(elem.clone())?);
-                } else if root.children().collect::<Vec<_>>().len() != 2 {
+                } else if root.children().count() != 2 {
                     return Err(Error::ParseError("Wrong number of children in iq element."));
                 }
             } else {

src/jingle_ft.rs

@@ -91,7 +91,7 @@ impl TryFrom<Element> for Description {
         if !elem.is("description", ns::JINGLE_FT) {
             return Err(Error::ParseError("This is not a JingleFT description element."));
         }
-        if elem.children().collect::<Vec<_>>().len() != 1 {
+        if elem.children().count() != 1 {
             return Err(Error::ParseError("JingleFT description element must have exactly one child."));
         }
 

src/presence.rs

@@ -485,6 +485,6 @@ mod tests {
         presence.statuses.insert(String::from(""), status);
         let elem: Element = presence.into();
         assert!(elem.is("presence", ns::JABBER_CLIENT));
-        assert!(elem.children().collect::<Vec<_>>()[0].is("status", ns::JABBER_CLIENT));
+        assert!(elem.children().next().unwrap().is("status", ns::JABBER_CLIENT));
     }
 }