You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: utf8.go
    path of file: ./repos/gotosocial/vendor/github.com/bytedance/sonic/utf8
    
    the code of the file until where you have to start completion: /*
 * Copyright 2022 ByteDance Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the 
    
func CorrectWith(dst []byte, src []byte, repl string) []byte {
    sstr := rt.Mem2Str(src)
    sidx := 0

    /* state machine records the invalid postions */
    m := types.NewStateMachine()
    m.Sp = 0 // invalid utf8 numbers

    for sidx < len(sstr) {
        scur  := sidx
        ecode := native.ValidateUTF8(&sstr, &sidx, m)

        if m.Sp != 0 {
            if m.Sp > len(sstr) {
                panic("numbers of invalid utf8 exceed the string len!")
            }
        }
        
        for i := 0; i < m.Sp; i++ {
            ipos := m.Vt[i] // invalid utf8 position
            dst  = append(dst, sstr[scur:ipos]...)
            dst  = append(dst, repl...)
            scur = m.Vt[i] + 1
        }
        /* append the remained valid utf8 bytes */
        dst = append(dst, sstr[scur:sidx]...)

        /* not enough space, reset and continue */
        if ecode != 0 {
            m.Sp = 0
        }
    }

    types.FreeStateMachine(m)
    return dst
}