Using switch statements on HTTP::headers

I'm trying to optimize some code that I've pulled from a couple of places and I was wondering if there's a way to use switch statements to check for the existence of headers, since I've read the switch statements are faster than if statements.

I'm mostly interested in combining my insertions into one switch statement (if possible) and my removal statements.

 This iRule combines Combine_cache_Control_Headers, Cookie_Encryption and removes some additional headers
 that might be useful to an attacker.

when RULE_INIT {
    
     This is for the BigIP cookie encryption
    
     Cookie name prefix
    set static::ck_pattern "BIGipServer*"
     Cookie encryption passphrase
     Change this to a custom string!
    set static::ck_pass "REMOVED"

    
     This is for the Cache header combiner
    
    set static::headers { "Cache-Control" "WWW-Authenticate" }
    set static::CacheHeaders { "Cache-Control" }

     Headers for removal
    set static::InfoHeaders { "Server" "X-Powered-By" }
}

when HTTP_REQUEST {

     Check if the cookie names in the request match our string glob pattern
    if {[set cookie_names [lsearch -all -inline [HTTP::cookie names] $static::ck_pattern]] ne ""}{
         We have at least one match so loop through the cookie(s) by name
        foreach cookie_name $cookie_names {
             Decrypt the cookie value and check if the decryption failed (null return value)
            if {[HTTP::cookie decrypt $cookie_name $static::ck_pass] eq ""}{
                HTTP::cookie remove $cookie_name
            }
        }
    }
}

when HTTP_RESPONSE { 

    
     Remove headers that provide information about the backend
    

    foreach header $static::InfoHeaders {
        if {[HTTP::header exists $header]} {
            HTTP::header remove $header
        }
    }

    
     Clickjacking mitigation
    
    if {![HTTP::header exists "Content-Security-Policy"] } {
       HTTP::header insert "Content-Security-Policy" "frame-ancestors 'self' example.com *.example.com"
    }

     MIME sniffing header
    if {![HTTP::header exists "X-Content-Type-Options"] } {
       HTTP::header insert "X-Content-Type-Options" "nosniff"
    }

     XSS header
    if {![HTTP::header exists "X-XSS-Protection"] } {
       HTTP::header insert "X-XSS-Protection" "1; mode=block"
    }

    
     Combine Cache headers so the acceleration profiles work correctly
    
    foreach header $static::CacheHeaders {
        if {[HTTP::header exists $header]} {
             Grab the values as a list, remove the existing headers, and
             replace with the values, joined as a comma-delimited string
            set from_values [HTTP::header values $header]
            set to_values {}
            foreach value $from_values {
                set value [string trim $value]
                if { $value ne ""} { lappend to_values $value }
            }
            set to_values [join $to_values ", "]
            HTTP::header remove $header
            HTTP::header insert "lws" $header $to_values
        }
    }

    
     Check if the cookie names in the request match our string glob pattern
    
    if {[set cookie_names [lsearch -all -inline [HTTP::cookie names] $static::ck_pattern]] ne ""}{
         We have at least one match so loop through the cookie(s) by name
        foreach cookie_name $cookie_names {
             Encrypt the cookie value
            HTTP::cookie encrypt $cookie_name $static::ck_pass
        }
    }
}