Umbrella issue for 26.0 testing. Please help testing on a wide variety of supported platforms, as well as interaction with different software.

Let us know which version you tested on which operating system.

If you find an issue, please search Github for known issues first and then open a new Github issue.

*This meta issue should not be used to report bugs, as a single thread makes it impossible to track more than one topic.*

See [26.0 Draft Release Notes](https://github.com/bitcoin-core/bitcoin-devwiki/wiki/26.0-Release-Notes-Draft) for a list of changes.

See here for the testing guide: https://github.com/bitcoin-core/bitcoin-devwiki/wiki/26.0-Release-Candidate-Testing-Guide.
{
        // if there is still any available memory left, put it into the freelist.
        size_t remaining_available_bytes = std::distance(m_available_memory_it, m_available_memory_end);
        if (0 != remaining_available_bytes) {
            PlacementAddToList(m_available_memory_it, m_free_lists[remaining_available_bytes / ELEM_ALIGN_BYTES]);
        }
        void* storage = ::operator new (m_chunk_size_bytes, std::align_val_t{ELEM_ALIGN_BYTES});
        m_available_memory_it = new (storage) std::byte[m_chunk_size_bytes];
        s;
        m_allocated_chunks.emplace_back(m_available_memory_it);
    }
    /**
     * Access to internals for testing purpose only
     */
    friend class PoolResourceTester;
public:
    /**
     * Construct a new PoolResource object which allocates the first chunk.
     * chunk_size_bytes will be rounded up to next multiple of ELEM_ALIGN_BYTES.
     */
    explicit PoolResource(std::size_t chunk_size_bytes)
        : m_chunk_size_bytes(NumElemAlignBytes(chunk_size_bytes) * ELEM_ALIGN_BYTES)
    {
        assert(m_chunk_size_bytes >= MAX_BLOCK_SIZE_BYTES);
        AllocateChunk();
    }
    /**
     * Construct a new Pool Resource object, defaults to 2^18=262144 chunk size.
     */
    PoolResource() : PoolResource(262144) {}