in auth-lib/src/main/java/com/spotify/sdk/android/auth/AuthorizationRequest.java [229:236]
private String scopesToString() {
StringBuilder concatScopes = new StringBuilder();
for (String scope : mScopes) {
concatScopes.append(scope);
concatScopes.append(SCOPES_SEPARATOR);
}
return concatScopes.toString().trim();
}