Add note about possible issues due to Proguard optimizing out the Android component

Author: complexspaces

README.md

@@ -93,6 +93,13 @@ new releases of `rustls-platform-verifier` are published. If you only use publis
 These script snippets can be tweaked as best suits your project, but the `cargo metadata` invocation must be included so that the Android
 implementation part can be located on disk.
 
+If your Android application makes use of Proguard for optimizations, its important to make sure that the Android verifier component isn't optimized 
+out because it looks like dead code". Proguard is unable to see any JNI usage, so your rules must manually opt into keeping it. THe following rule
+can do this for you:
+```text
+-keep, includedescriptorclasses class org.rustls.platformverifier.** { *; }
+```
+
 #### Crate initialization
 
 In order for the crate to call into the JVM, it needs handles from Android. These