https://timsong-cpp.github.io/cppwp/n3337/filebuf.members
[filebuf.members]
members
https://gcc.gnu.org/pipermail/gcc-bugs/2003-March/073642.html
libstdc++/10096: Input impossible with basic_filebuf with custom traits type.
inputimpossiblebasiccustomtraits
https://timsong-cpp.github.io/cppwp/n4861/filebuf.cons
[filebuf.cons]
cons
https://gcc.gnu.org/pipermail/gcc-bugs/2003-March/073084.html
libstdc++/9988: filebuf::overflow writes EOF to file
overflowwriteseoffile