* fix: rename variable to avoid shadow warning w/UTP
* fix: add default dtor for tr_strbuf
* fix: implicit conversion may lose precision
* fix: use init-statement to reduce variable scope
* fix: implicit conversion may lose precision
* fix: extract the assignment from this expression
* fix: use init-statement to reduce variable scope
* fix: use init-statement to reduce variable scope
* fix: do not mix public and private data members
* fix: add a condition to cv.wait call
* fix: do not throw uncaught exceptions in destructor
* feat: add tr_strbuf class for building tmp strings
Based on fmt::basic_memory_buf, this is a growable string buffer that
has an initial size that's large enough to build most filenames or URLs
without needing heap allocations.
Adds a couple of extra helpers such as a `c_str()` method to make dealing
with old zero-terminated string APIs easier.
Julien