Use constant

import okio.ByteString

import java.io.IOException

import java.nio.ByteBuffer

import java.nio.charset.Charset

import java.util.*

import java.util.concurrent.atomic.AtomicInteger

                 So, UTF-8 encoding for credentials is compatible with all RFC 7617 servers and many,

                 but not all pre-RFC 7617 servers. */

                return request.newBuilder()

                        .header(HEADER_AUTHORIZATION, Credentials.basic(username, password, Charset.forName("UTF-8")))

                        .header(HEADER_AUTHORIZATION, Credentials.basic(username, password, Charsets.UTF_8))

                        .build()

            }