Use <iosfwd> instead of <ostream>

include/beast/http/impl/serializer.ipp

@@ -13,7 +13,6 @@
 #include <boost/assert.hpp>
 #include <ostream>
 
-
 namespace beast {
 namespace http {
 namespace detail {

include/beast/http/status.hpp

@@ -10,7 +10,7 @@
 
 #include <beast/config.hpp>
 #include <beast/core/string_view.hpp>
-#include <ostream>
+#include <iosfwd>
 
 namespace beast {
 namespace http {

include/beast/http/verb.hpp

@@ -10,7 +10,7 @@
 
 #include <beast/config.hpp>
 #include <beast/core/string_view.hpp>
-#include <ostream>
+#include <iosfwd>
 
 namespace beast {
 namespace http {

include/beast/http/write.hpp

@@ -19,9 +19,9 @@
 #include <beast/core/async_result.hpp>
 #include <beast/core/string_view.hpp>
 #include <boost/variant.hpp>
+#include <iosfwd>
 #include <limits>
 #include <memory>
-#include <ostream>
 #include <type_traits>
 #include <utility>