class RbSys::ExtensionTask

@return [Rake::ExtensionTask]
@param gem_spec [Gem::Specification] the gem specification to build (needed for cross-compiling)
@param name [String] the crate name to build
end
ext.lib_dir = “lib/my-crate”
RbSys::ExtensionTask.new(“my-crate”, my_gemspec) do |ext|
@example
@see www.rubydoc.info/gems/rake-compiler/Rake/ExtensionTask<br><br>Rust extensions. It has the same options a ‘Rake::ExtensionTask`.
ExtensionTask is a Rake::ExtensionTask subclass that is used to tailored for

def binary(_platf) 

def binary(_platf)
  super.tr("-", "_")
end

def cargo_metadata 

def cargo_metadata
  @cargo_metadata ||= Cargo::Metadata.new(@name)
end

def cross_compiling(&block) 

def cross_compiling(&block)
  @cross_compiling_blocks << block if block
end

def define 

def define
  super
  define_env_tasks
end

def define_env_tasks 

def define_env_tasks
  task "rb_sys:env:default" do
    ENV["RB_SYS_CARGO_TARGET_DIR"] ||= target_directory
    ENV["RB_SYS_CARGO_MANIFEST_DIR"] ||= cargo_metadata.manifest_directory
    ENV["RB_SYS_CARGO_PROFILE"] ||= "release"
  end
  desc "Use the debug profile for building native Rust extensions"
  task "rb_sys:env:dev" do
    ENV["RB_SYS_CARGO_PROFILE"] = "dev"
  end
  desc "Use the release profile for building native Rust extensions"
  task "rb_sys:env:release" do
    ENV["RB_SYS_CARGO_PROFILE"] = "release"
  end
  file extconf => "rb_sys:env:default"
  desc 'Compile the native Rust extension with the "dev" profile'
  task "compile:dev" => ["rb_sys:env:dev", "compile"]
  desc 'Compile the native Rust extension with the "release" profile'
  task "compile:release" => ["rb_sys:env:release", "compile"]
end

def define_native_tasks(for_platform = nil, ruby_ver = RUBY_VERSION, callback = nil) 

def define_native_tasks(for_platform = nil, ruby_ver = RUBY_VERSION, callback = nil)
  cb = proc do |gemspec|
    callback&.call(gemspec)
    @cross_compiling_blocks.each do |block|
      block.call(gemspec)
    end
  end
  super(for_platform, ruby_ver, cb)
end

def extconf 

def extconf
  File.join(cargo_metadata.manifest_directory, "extconf.rb")
end

def init(name = nil, gem_spec = nil) 

def init(name = nil, gem_spec = nil)
  super
  @orginal_ext_dir = @ext_dir
  @ext_dir = cargo_metadata.manifest_directory
  @source_pattern = nil
  @compiled_pattern = "*.{obj,so,bundle,dSYM}"
  @cross_compile = ENV.key?("RUBY_TARGET")
  @cross_platform = [ENV["RUBY_TARGET"]].compact
  @cross_compiling_blocks = []
  @cross_compiling_blocks << proc do |gemspec|
    warn "Removing unneeded dependencies from native gemspec"
    gemspec.dependencies.reject! { |d| d.name == "rb_sys" }
  end
  @cross_compiling_blocks << proc do |gemspec|
    warn "Removing source files from native gemspec"
    gemspec.files.reject! { |f| f.end_with?(".rs") }
    gemspec.files.reject! { |f| f.match?(/Cargo.(toml|lock)$/) }
    gemspec.files.reject! { |f| extconf.end_with?(f) }
  end
end

def source_files

I'm not sure why this is necessary, can it be removed? 
def source_files
  list = FileList[
    "#{ext_dir}/**/*.{rs,rb,c,h,toml}",
    "**/Cargo.{toml,lock}",
    "**/.cargo/**/*",
    "#{ext_dir}/lib/**/*"
  ]
  list.include("#{ext_dir}/#{@source_pattern}") if @source_pattern
  list.exclude(File.join(target_directory, "**/*"))
  list
end

def target_directory 

def target_directory
  cargo_metadata.target_directory
end