SPDX standardizes how source code conveys its copyright and licensing
information. See https://spdx.github.io/spdx-spec/1-rationale/ . SPDX
tags are adopted in many large projects, including things like the Linux
kernel.
This variable isn't std::moved anywhere and is just read out of into a
string. Instead of making a copy, and then another copy of the data into
a std::string, we can take it by reference, only copying the data once.
This isn't std::moved wholesale into a member variable or further
std::moved into another function, so it's better to take it by const
reference here to avoid unnecessary reallocations of contained
std::string instances.
Moves it closer to where its used, narrowing its visible scope, as well
as preventing unnecessary std::string constructor executions in the
event invalid data is encountered (the continue branch).
std::function is allowed to heap allocate in order to store captured
variables, etc, so std::function isn't a trivial type. We can std::move
here in order to avoid potential reallocating.
While we're at it, make the definition's parameter name match the
declaration's parameter name for consistency.
If the parameter is const, then a move won't actually be able to occur,
making the std::move non-functional. We can remove the const qualifier
to remedy this.
We can't join a detached thread, so NetPlayIndex gets deleted before
the notification thread exits, creating a race condition. We switch to
using Common::Event because just sleeping leaves the UI hung on the
thread join for a few seconds.
