This tutorial is based on Linux, and supposing you are familiar with Android NDK, Rust and Flutter. If you are not, please skip.
# For saving your time and our time, we prepared dependent files for you.
tar xzf dep.tar.gz
# please use r22b, new NDK has below problem
# install ffigen and llvm
dart pub global activate ffigen 5.0.1
# on Ubuntu 18, it is: sudo apt install libclang-9-dev
sudo apt-get install libclang-dev
git clone https://github.com/rustdesk/rustdesk
rustup target add aarch64-linux-android
cargo install cargo-ndk
VCPKG_ROOT=$HOME/vcpkg ANDROID_NDK_HOME=$HOME/android-ndk-r22b flutter/ndk_arm64.sh
tar xzf so.tar.gz
cp ../target/aarch64-linux-android/release/liblibrustdesk.so android/app/src/main/jniLibs/arm64-v8a/librustdesk.so
# Run on your android device, not support simulator yet (Please do not ask why).
# Good Luck!
# openjdk 11 required, do not use higher or lower, both has problem