How to use the aiokafka.record.util.size_of_varint function in aiokafka

def size_of(cls, key, value, headers):
        size = 0
        # Key size
        if key is None:
            size += 1
        else:
            key_len = len(key)
            size += size_of_varint(key_len) + key_len
        # Value size
        if value is None:
            size += 1
        else:
            value_len = len(value)
            size += size_of_varint(value_len) + value_len
        # Header size
        size += size_of_varint(len(headers))
        for h_key, h_value in headers:
            h_key_len = len(h_key.encode("utf-8"))
            size += size_of_varint(h_key_len) + h_key_len

            if h_value is None:
                size += 1
            else:
                h_value_len = len(h_value)
                size += size_of_varint(h_value_len) + h_value_len
        return size

def size_of(cls, key, value, headers):
        size = 0
        # Key size
        if key is None:
            size += 1
        else:
            key_len = len(key)
            size += size_of_varint(key_len) + key_len
        # Value size
        if value is None:
            size += 1
        else:
            value_len = len(value)
            size += size_of_varint(value_len) + value_len
        # Header size
        size += size_of_varint(len(headers))
        for h_key, h_value in headers:
            h_key_len = len(h_key.encode("utf-8"))
            size += size_of_varint(h_key_len) + h_key_len

            if h_value is None:
                size += 1
            else:
                h_value_len = len(h_value)
                size += size_of_varint(h_value_len) + h_value_len
        return size

if value is None:
            size += 1
        else:
            value_len = len(value)
            size += size_of_varint(value_len) + value_len
        # Header size
        size += size_of_varint(len(headers))
        for h_key, h_value in headers:
            h_key_len = len(h_key.encode("utf-8"))
            size += size_of_varint(h_key_len) + h_key_len

            if h_value is None:
                size += 1
            else:
                h_value_len = len(h_value)
                size += size_of_varint(h_value_len) + h_value_len
        return size

def size_of(cls, key, value, headers):
        size = 0
        # Key size
        if key is None:
            size += 1
        else:
            key_len = len(key)
            size += size_of_varint(key_len) + key_len
        # Value size
        if value is None:
            size += 1
        else:
            value_len = len(value)
            size += size_of_varint(value_len) + value_len
        # Header size
        size += size_of_varint(len(headers))
        for h_key, h_value in headers:
            h_key_len = len(h_key.encode("utf-8"))
            size += size_of_varint(h_key_len) + h_key_len

            if h_value is None:
                size += 1
            else:
                h_value_len = len(h_value)

def size_in_bytes(self, offset, timestamp, key, value, headers):
        if self._first_timestamp is not None:
            timestamp_delta = timestamp - self._first_timestamp
        else:
            timestamp_delta = 0
        size_of_body = (
            1 +  # Attrs
            size_of_varint(offset) +
            size_of_varint(timestamp_delta) +
            self.size_of(key, value, headers)
        )
        return size_of_body + size_of_varint(size_of_body)

def size_in_bytes(self, offset, timestamp, key, value, headers):
        if self._first_timestamp is not None:
            timestamp_delta = timestamp - self._first_timestamp
        else:
            timestamp_delta = 0
        size_of_body = (
            1 +  # Attrs
            size_of_varint(offset) +
            size_of_varint(timestamp_delta) +
            self.size_of(key, value, headers)
        )
        return size_of_body + size_of_varint(size_of_body)

def size_in_bytes(self, offset, timestamp, key, value, headers):
        if self._first_timestamp is not None:
            timestamp_delta = timestamp - self._first_timestamp
        else:
            timestamp_delta = 0
        size_of_body = (
            1 +  # Attrs
            size_of_varint(offset) +
            size_of_varint(timestamp_delta) +
            self.size_of(key, value, headers)
        )
        return size_of_body + size_of_varint(size_of_body)

if key is None:
            size += 1
        else:
            key_len = len(key)
            size += size_of_varint(key_len) + key_len
        # Value size
        if value is None:
            size += 1
        else:
            value_len = len(value)
            size += size_of_varint(value_len) + value_len
        # Header size
        size += size_of_varint(len(headers))
        for h_key, h_value in headers:
            h_key_len = len(h_key.encode("utf-8"))
            size += size_of_varint(h_key_len) + h_key_len

            if h_value is None:
                size += 1
            else:
                h_value_len = len(h_value)
                size += size_of_varint(h_value_len) + h_value_len
        return size