message: Print new_data_msg content hex formatted
diff: #include <iomanip>
  #include "caf/meta/type_name.hpp"
  +#include "caf/meta/hex_formatted.hpp"
  #include "caf/io/handle.hpp"
  #include "caf/io/accept_handle.hpp"
  @@ -58,7 +59,8 @@ struct new_data_msg {
  /// @relates new_data_msg
  template <class Inspector>
  typename Inspector::result_type inspect(Inspector& f, new_data_msg& x) {
  - return f(meta::type_name("new_data_msg"), x.handle, x.buf);
  + return f(meta::type_name("new_data_msg"), x.handle,
  + meta::hex_formatted(), x.buf);
  }
  /// Signalizes that a certain amount of bytes has been written.
  