为什么 NSResponder 中的 interpretKeyEvents 会忽略某些重复的键？

问：

我有一个调用事件的 NSView。对于某些键（如字母“a”），按住该键会导致重复调用 。对于其他键，如“x”，调用一次，仅此而已。我想按住始终拨打 。我猜按住这些键被解释为其他东西，但我找不到它。我已经按照文档的描述实现了，但也从未调用过。interpretKeyEventskeyDowninsertTextinsertTextinsertTextdoCommandBySelector

下面是一个演示该行为的最小示例程序。

// clang++ -framework AppKit -o proof-of-concept proof-of-concept.mm

#include <stdio.h>
#import <Cocoa/Cocoa.h>

@interface AppView : NSView<NSTextInputClient>
@end

@implementation AppView

- (void)keyDown:(NSEvent *)event {
    printf("keydown\n");
    [self interpretKeyEvents:[NSArray arrayWithObject:event]];
}

- (void)insertText:(id)string replacementRange:(NSRange)replacementRange {
    printf("insertText\n");
}

- (BOOL)acceptsFirstResponder { return YES; }
- (void)setMarkedText:(id)string selectedRange:(NSRange)selectedRange replacementRange:(NSRange)replacementRange {}
- (void)unmarkText {}
- (NSRange)selectedRange { return NSMakeRange(NSNotFound, 0); }
- (NSRange)markedRange { return NSMakeRange(NSNotFound, 0); }
- (BOOL)hasMarkedText { return NO; }
- (nullable NSAttributedString *)attributedSubstringForProposedRange:(NSRange)range actualRange:(nullable NSRangePointer)actualRange { return nil; }
- (NSArray<NSAttributedStringKey> *)validAttributesForMarkedText { return [NSArray array]; }
- (NSRect)firstRectForCharacterRange:(NSRange)range actualRange:(nullable NSRangePointer)actualRange { return NSMakeRect(0, 0, 0, 0); }
- (NSUInteger)characterIndexForPoint:(NSPoint)point { return 0; }

@end

int main(int argc, char **argv, char **envp, char **apple) {
    [NSApplication sharedApplication];
    [NSApp setActivationPolicy:NSApplicationActivationPolicyRegular];

    NSRect windowDimensions = NSMakeRect(0, 0, 300, 300);
    NSWindow *window = [[NSWindow alloc] initWithContentRect:windowDimensions
                                         styleMask:NSWindowStyleMaskTitled | NSWindowStyleMaskResizable
                                         backing:NSBackingStoreBuffered
                                         defer:NO];

    AppView *windowView = [[AppView alloc] initWithFrame:windowDimensions];
    [window setContentView:windowView];
    [window makeKeyAndOrderFront:nil];

    [NSApp run];
    return 0;
}

有没有解释为什么通过调用来处理一些键重复而忽略其他键？interpretKeyEventsinsertText