New ostream() returns dynamic buffer output stream (API Change):

This eliminates beast::write output for dynamic buffers and replaces
it with the function ostream() that wraps a caller provided dynamic
buffer and returns the result as a std::ostream derived object.
Callers may now produce formatted output into any object meeting the
requirements of DynamicBuffer using operator<< and the standard stream
modifiers such as std::endl.

This new technique is more efficient, as implementations of operator<<
can now write directly into the output using std::ostream::write and
std::ostream::put.

Example of use:

  beast::streambuf sb;
  beast::ostream(sb) << "Hello, world!" << std::endl;

test/core/streambuf.cpp

@@ -273,13 +273,6 @@ public:
         BEAST_EXPECT(test::buffer_count(sb.data()) == 4);
     }
 
-    void testOutputStream()
-    {
-        streambuf sb;
-        sb << "x";
-        BEAST_EXPECT(to_string(sb.data()) == "x");
-    }
-
     void testCapacity()
     {
         using boost::asio::buffer_size;
@@ -353,7 +346,6 @@ public:
         testConsume();
         testMatrix();
         testIterators();
-        testOutputStream();
         testCapacity();
     }
 };