Clarify UPX section

Author: johnthagen

README.md

@@ -49,17 +49,6 @@ Available starting `1.45.0-nightly (2020-05-28)`,
 $ cargo +nightly build -Z strip=symbols
 ```
 
-# Compress the binary
-
-[`uxp`](https://github.com/upx/upx) is a powerful tool for creating a self contained, compressed binary with no addition
-runtime requirements.  It claims to typically reduce file size by 50-70% but the actual result depends on your
-executable.  For our example we see a respectable 23% reduction.
-
-```bash
-$ uxp --best --lzma target/release/min-sized-rust
-```
-
-
 # Optimize For Size
 
 ![Minimum Rust: 1.28](https://img.shields.io/badge/Minimum%20Rust%20Version-1.28-brightgreen.svg)
@@ -301,6 +290,22 @@ fn my_panic(_info: &core::panic::PanicInfo) -> ! {
 }
 ```
 
+# Compress the binary
+
+Up until this point, all size-reducing techniques were Rust-specific. This section describes
+a language-agnostic binary packing tool that is an option to reduce binary size further.
+
+[UPX](https://github.com/upx/upx) is a powerful tool for creating a self contained, compressed
+binary with no addition runtime requirements.  It claims to typically reduce binary size by 50-70%,
+but the actual result depends on your executable.
+
+```bash
+$ upx --best --lzma target/release/min-sized-rust
+```
+
+It should be noted that there have been times that UPX-packed binaries have flagged
+heuristic-based anti-virus software because malware often uses UPX.
+
 # Tools
 
 - [`cargo-bloat`](https://github.com/RazrFalcon/cargo-bloat) - Find out what takes most of the