* length of the local certificate chain. These certificates are also base64-encoded and appear
     * each on their own line. A length of -1 is used to encode a null array. The last line is
     * optional. If present, it contains the TLS version.
     */
    @Throws(IOException::class)
    constructor(rawSource: Source) {
      rawSource.use {
        val source = rawSource.buffer()