src: avoid name clash with upper scope in node_trace_buffer.cc

[gengjiawen]

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• commit message follows commit guidelines

[addaleax]

This conflicts with #25896.

I also find it confusing: These are the same objects, so referring to them by the same name makes sense, right?

[gengjiawen]

They are in the same function, so better with different name IMHO.

[gengjiawen]

Current there is three buffer in this method, give those different name will make it more readable

[gengjiawen]

@addaleax give this another thought or leave it the old way ?

[addaleax]

@gengjiawen Yeah, I’m still -1 on doing this. You can wait for others to chime in, if you want.