presto-kafka/src/main/java/io/prestosql/plugin/kafka/KafkaSplitManager.java/KafkaSplitManager/readSchema
class KafkaSplitManager:    private static String readSchema(String dataSchemaLocation)
    {
        InputStream inputStream = null;
        try {
            if (isURI(dataSchemaLocation.trim().toLowerCase(ENGLISH))) {
                try {
                    inputStream = new URL(dataSchemaLocation).openStream();
                }
                catch (MalformedURLException e) {
                    // try again before failing
                    inputStream = new FileInputStream(dataSchemaLocation);
                }
            }
            else {
                inputStream = new FileInputStream(dataSchemaLocation);
            }
            return CharStreams.toString(new InputStreamReader(inputStream, UTF_8));
        }
        catch (IOException e) {
            throw new PrestoException(GENERIC_INTERNAL_ERROR, "Could not parse the Avro schema at: " + dataSchemaLocation, e);
        }
        finally {
            closeQuietly(inputStream);
        }
    }