add `__unused`

Xcode 忽略警告.m

#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Warc-performSelector-leaks"
		// Start executing the requested task
		[targetForExecution performSelector:methodForExecution withObject:objectForExecution];
#pragma clang diagnostic pop

"-Wgnu"

"-Warc-performSelector-leaks"
"-Warc-retain-cycles"

"-Wobjc-interface-ivars"

"-Wdeprecated-implementations"
"-Wdeprecated-declarations"

"-Wunreachable-code"

"-Wimplicit-atomic-properties"

"-Wcovered-switch-default"

"-Wassign-enum"

"-Wimplicit-retain-self"

"-Wundeclared-selector"
"-Wundeclared-selector"

`__unused` / `__attribute__((unused))` 忽略没有使用变量属性而引起的警告