Reconsider how users use offloadNone strategy while some filters block

Existing approach is that if users specify `offloadNone()` execution strategy on the builder, we respect that and disable offloading. However, if they have a filter that for sure has blocking code, it will hurt users if we are silent about it. Consider the following improvement options:
- still add offloading based on the filter chain requirements and log that the computed value is different from what was specified;
- throw an exception describing what filter does not allow using `offloadNone()`
- keep the offloading disabled, but warn users that they have a blocking code in the filter chain

Start at the builder's offloadNone() handling and the filter-chain blocking requirement calculation. Compare the three behavior options described in the issue, including how users would be informed when blocking filters are present. Done means selecting and implementing a clear, documented behavior for this combination.

Written by the indexing model from the issue text.