@Nullable
	@Override
	public byte[] chunk(@NonNull final byte[] message,
						@IntRange(from = 0) final int index,
						@IntRange(from = 20) final int maxLength) {
		final int offset = index * maxLength;
		final int length = Math.min(maxLength, message.length - offset);

		if (length <= 0)
			return null;

		final byte[] data = new byte[length];
		System.arraycopy(message, offset, data, 0, length);
		return data;
	}
Splits the message into at-most MTU-3 size packets.
ble/src/main/java/no/nordicsemi/android/ble/data/DefaultMtuSplitter.java