What version of Hono are you using?

4.9.10

What runtime/platform is your app running on? (with version if possible)

What steps can reproduce the bug?

simply call setCookie with the same key multiple times, e.g.:

setCookie(c, 'hello', 'world1')
setCookie(c, 'hello', 'world2')
setCookie(c, 'hello', 'world3')

What is the expected behavior?

Only the last call's data is sent, i.e.:

set-cookie:
hello=world3; Path=/

What do you see instead?

set-cookie:
hello=world1; Path=/
set-cookie:
hello=world2; Path=/
set-cookie:
hello=world3; Path=/

The response includes multiple Set-Cookie header for the same key, wasting unnecessary bandwidth and possibly prone to error with the receiving client's parser.

Additional information

No response