message: Add an example to lazy_query
diff: @@ -237,6 +237,29 @@ impl<'conn> Statement<'conn> {
  /// `Connection` as this `Statement`, if the `Transaction` is not
  /// active, or if the number of parameters provided does not match the
  /// number of parameters expected.
  + ///
  + /// # Examples
  + ///
  + /// ```no_run
  + /// extern crate fallible_iterator;
  + /// extern crate postgres;
  + ///
  + /// use fallible_iterator::FallibleIterator;
  + /// # use postgres::{Connection, TlsMode};
  + ///
  + /// # fn main() {
  + /// # let conn = Connection::connect("", TlsMode::None).unwrap();
  + /// let stmt = conn.prepare("SELECT foo FROM bar WHERE baz = $1").unwrap();
  + /// let trans = conn.transaction().unwrap();
  + /// # let baz = true;
  + /// let mut rows = stmt.lazy_query(&trans, &[&baz], 100).unwrap();
  + ///
  + /// while let Some(row) = rows.next().unwrap() {
  + /// let foo: i32 = row.get("foo");
  + /// println!("foo: {}", foo);
  + /// }
  + /// # }
  + /// ```
  pub fn lazy_query<'trans, 'stmt>(
  &'stmt self,
  trans: &'trans Transaction,
  