Reads and decrypts if necessary the compressed blocks, but doesnotdecompress them. The totality of the data is stored in FIoStoreCompressedReadResult::FIoBuffer as a contiguous buffer, however each block is padded during encryption, so either useFIoStoreCompressedBlockInfo::AlignedSizeto advance through the buffer, or useFIoStoreCompressedBlockInfo::OffsetInBufferdirectly.