Am I misunderstanding the doc for @logmsg?

General Usage
1

I’m trying to write a macro to customize the behavior of logging a bit.

Logging · The Julia Language says

_file=string and _line=integer can be used to override the apparent source location of a log message.

This test file illustrates a problem I’m having concerning reporting the line number where the logging is done:

using Logging

ENABLE_MY_LOGGING = false

function with_my_logging(f, level)
    global ENABLE_MY_LOGGING
    previous = ENABLE_MY_LOGGING
    try
        ENABLE_MY_LOGGING = level
        f()
    finally
        ENABLE_MY_LOGGING = previous
    end
end

macro my_logging(args...)
    logargs = [ :_file => __source__.file,
                :_line => __source__.line,
                :_module => __module__,
                # ERROR: LoadError: MethodError: no method matching iterate(::Expr)
                # args...
                ]
    :(
        if ENABLE_MY_LOGGING isa LogLevel
            @logmsg(ENABLE_MY_LOGGING,
                    "My logging message",
                    $logargs...)            
        end
    )
end

with_logger(SimpleLogger(stdout, Logging.Debug)) do

    with_my_logging(Logging.Debug) do
        @my_logging(v1=2, v2="foo")
    end
    
    with_my_logging(Logging.Debug) do
        @my_logging(foo="bar")
    end
end

When I run it

julia logtest.jl
  Activating environment at `c:\Users\Mark Nahabedian\.julia\dev\Unification\Project.toml`
┌ Debug: My logging message
│   _file = c:\Users\Mark Nahabedian\.julia\dev\Unification\logtest.jl
│   _line = 36
│   _module = Main
└ @ Main c:\Users\Mark Nahabedian\.julia\dev\Unification\logtest.jl:26
┌ Debug: My logging message
│   _file = c:\Users\Mark Nahabedian\.julia\dev\Unification\logtest.jl
│   _line = 40
│   _module = Main
└ @ Main c:\Users\Mark Nahabedian\.julia\dev\Unification\logtest.jl:26

Note that the reported values of _line are what I expect, not the line number reported on the last line of each log message.