Disable Mixpanel's AB Testing.

Podfile

post_install do |installer|
    installer.pods_project.targets.each do |target|
        if target.name == 'Mixpanel'
            target.build_configurations.each do |config|
                puts "  Pods-Mixpanel #{config.name} before: #{config.build_settings['GCC_PREPROCESSOR_DEFINITIONS'].inspect}"
                config.build_settings['GCC_PREPROCESSOR_DEFINITIONS'] ||= ['$(inherited)']
                config.build_settings['GCC_PREPROCESSOR_DEFINITIONS'] << 'DISABLE_MIXPANEL_AB_DESIGNER=1'
                puts "  Pods-Mixpanel #{config.name} after:  #{config.build_settings['GCC_PREPROCESSOR_DEFINITIONS'].inspect}"
            end
        end
    end
end