Flutter Execution failed for task ':iris_method_channel:buildCMakeDebug[arm64-v8a]'

Unable to run flutter app due to following exception.

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':iris_method_channel:buildCMakeDebug[arm64-v8a]'.
> com.android.ide.common.process.ProcessException: ninja: Entering directory `/home/muhammad/.pub-cache/hosted/pub.dev/iris_method_channel-1.1.0-rc.5/android/.cxx/Debug/2i83q535/arm64-v8a'
  [1/2] Building CXX object CMakeFiles/iris_method_channel.dir/iris_event.cc.o
  FAILED: CMakeFiles/iris_method_channel.dir/iris_event.cc.o 
  /home/muhammad/Android/Sdk/ndk/23.1.7779620/toolchains/llvm/prebuilt/linux-x86_64/bin/clang++ --target=aarch64-none-linux-android21 --gcc-toolchain=/home/muhammad/Android/Sdk/ndk/23.1.7779620/toolchains/llvm/prebuilt/linux-x86_64 --sysroot=/home/muhammad/Android/Sdk/ndk/23.1.7779620/toolchains/llvm/prebuilt/linux-x86_64/sysroot -DDART_SHARED_LIB -Diris_method_channel_EXPORTS  -g -DANDROID -fdata-sections -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -D_FORTIFY_SOURCE=2 -Wformat -Werror=format-security   -fno-limit-debug-info  -fPIC -MD -MT CMakeFiles/iris_method_channel.dir/iris_event.cc.o -MF CMakeFiles/iris_method_channel.dir/iris_event.cc.o.d -o CMakeFiles/iris_method_channel.dir/iris_event.cc.o -c /home/muhammad/.pub-cache/hosted/pub.dev/iris_method_channel-1.1.0-rc.5/src/iris_event.cc
  In file included from /home/muhammad/.pub-cache/hosted/pub.dev/iris_method_channel-1.1.0-rc.5/src/iris_event.cc:6:
  /snap/flutter/current/usr/include/c++/9/memory:121:25: error: cast from pointer to smaller type 'uintptr_t' (aka 'unsigned int') loses information
    const auto __intptr = reinterpret_cast<uintptr_t>(__ptr);
                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  /home/muhammad/.pub-cache/hosted/pub.dev/iris_method_channel-1.1.0-rc.5/src/iris_event.cc:90:17: error: use of undeclared identifier 'memcpy'; did you mean 'wmemcpy'?
                  memcpy(abuffer, obuffer, abufferLength);
                  ^~~~~~
                  wmemcpy
  /snap/flutter/current/usr/include/wchar.h:262:17: note: 'wmemcpy' declared here
  extern wchar_t *wmemcpy (wchar_t *__restrict __s1,
                  ^
  /home/muhammad/.pub-cache/hosted/pub.dev/iris_method_channel-1.1.0-rc.5/src/iris_event.cc:90:24: error: cannot initialize a parameter of type 'wchar_t *' with an lvalue of type 'uint8_t *' (aka 'unsigned char *')
                  memcpy(abuffer, obuffer, abufferLength);
                         ^~~~~~~
  /snap/flutter/current/usr/include/wchar.h:262:46: note: passing argument to parameter '__s1' here
  extern wchar_t *wmemcpy (wchar_t *__restrict __s1,
                                               ^
  3 errors generated.
  ninja: build stopped: subcommand failed.

  C++ build system [build] failed while executing:
      /home/muhammad/Android/Sdk/cmake/3.18.1/bin/ninja \
        -C \
        /home/muhammad/.pub-cache/hosted/pub.dev/iris_method_channel-1.1.0-rc.5/android/.cxx/Debug/2i83q535/arm64-v8a \
        iris_method_channel
    from /home/muhammad/.pub-cache/hosted/pub.dev/iris_method_channel-1.1.0-rc.5/android

* Try:
> Run with --stacktrace option to get the stack trace.
> Run with --info or --debug option to get more log output.
> Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 2m 18s
Exception: Gradle task assembleDebug failed with exit code 1

• iris_method_channel is used by agora_rtc_engine.

• I am using

   agora_rtc_engine: ^6.1.1
  

• I have updated my flutter as well. Tried many things but no result
  found

Installing the Flutter SDK manually (see docs) resolved the issue in Ubuntu.

All the credit goes to this answer.