public static CallCredentials authorizationHeader(final Supplier<String> authorizationSource) {
        requireNonNull(authorizationSource, "authorizationSource");

        return authorizationHeaders(() -> {
            final Metadata extraHeaders = new Metadata();
            extraHeaders.put(AUTHORIZATION_HEADER, authorizationSource.get());
            return extraHeaders;
        });
    }
Creates new call credentials with the given authorization information source.

<p>
<b>Note:</b> This method uses experimental grpc-java-API features.
</p>

@param authorizationSource The authorization source to use. The authorization usually starts with the scheme such
       as as {@code "Basic "} or {@code "Bearer "} followed by the actual authentication information.
@return The newly created call credentials.
@see SecurityConstants#AUTHORIZATION_HEADER
@see #authorizationHeaders(Supplier)
grpc-client-spring-boot-starter/src/main/java/net/devh/boot/grpc/client/security/CallCredentialsHelper.java