jodd-core/src/main/java/jodd/io/upload/MultipartRequestInputStream.java
public int copyMax(final OutputStream out, final int maxBytes) throws IOException {
		int count = 0;
		while (true) {
			byte b = readByte();
			if (isBoundary(b)) {
				break;
			}
			out.write(b);
			count++;
			if (count == maxBytes) {
				return count;
			}
		}
		return count;
	}
public int copyMax(final OutputStream out, final int maxBytes) throws IOException {
		int count = 0;
		while (true) {
			byte b = readByte();
			if (isBoundary(b)) {
				break;
			}
			out.write(b);
			count++;
			if (count == maxBytes) {
				return count;
			}
		}
		return count;
	}
Copies max or less number of bytes to output stream. Useful for determining
if uploaded file is larger then expected.