@Deprecated
    public static int getStreamBufferSize() {
        int streamBufferSize = DEFAULT_STREAM_BUFFER_SIZE;
        String bufferSizeOverride =
            System.getProperty(SDKGlobalConfiguration.DEFAULT_S3_STREAM_BUFFER_SIZE);

        if (bufferSizeOverride != null) {
            try {
                streamBufferSize = Integer.parseInt(bufferSizeOverride);
            } catch (Exception e) {
                log.warn("Unable to parse buffer size override from value: " + bufferSizeOverride);
            }
        }
        return streamBufferSize;
    }
Returns the buffer size override if it is specified in the system property,
otherwise returns the default value.
aws-java-sdk-s3/src/main/java/com/amazonaws/services/s3/internal/Constants.java