./ns3/timer-impl.h:683:12: error: use of deleted function ‘std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator=(const std::basic_ostream<_CharT, _Traits>&) [with _CharT = char; _Traits = std::char_traits<char>]’
683 | m_a1 = a1;
| ~~~~~^~~~
In file included from /usr/include/c++/9/istream:39,
from /usr/include/c++/9/fstream:38,
from ../src/ndnSIM/utils/tracers/pit-tracer.hpp:4,
from ../src/ndnSIM/utils/tracers/pit-tracer.cpp:1:
/usr/include/c++/9/ostream:405:22: note: declared here
405 | basic_ostream& operator=(const basic_ostream&) = delete;
| ^~~~~~~~
How to deal with the above error? Any Ideas? Thanks for your help in advance.