public static SchemaBuilder map(Schema keySchema, Schema valueSchema) {
        if (null == keySchema)
            throw new SchemaBuilderException("keySchema cannot be null.");
        if (null == valueSchema)
            throw new SchemaBuilderException("valueSchema cannot be null.");
        SchemaBuilder builder = new SchemaBuilder(Type.MAP);
        builder.keySchema = keySchema;
        builder.valueSchema = valueSchema;
        return builder;
    }
@param keySchema the schema for keys in the map
@param valueSchema the schema for values in the map
@return a new {@link Schema.Type#MAP} SchemaBuilder
connect/api/src/main/java/org/apache/kafka/connect/data/SchemaBuilder.java