Read the whole sector instead of record chunks on Windows to speed up…

… proving process

crates/subspace-farmer-components/src/reading.rs

@@ -151,9 +151,32 @@ where
     let sector_contents_map_size = SectorContentsMap::encoded_size(pieces_in_sector) as u64;
     match sector {
         ReadAt::Sync(sector) => {
+            // TODO: Random reads are slow on Windows due to a variety of bugs with its disk
+            //  subsystem:
+            //    * https://learn.microsoft.com/en-us/answers/questions/1601862/windows-is-leaking-memory-when-reading-random-chun
+            //    * https://learn.microsoft.com/en-us/answers/questions/1608540/getfileinformationbyhandle-followed-by-read-with-f
+            //    * and likely some more that are less obvious
+            //  As a workaround, read the whole sector at once instead of individual record chunks,
+            //  which while results in higher data transfer from SSD, reads data in larger blocks
+            //  and ends up being faster in many cases even though it uses more RAM while doing so.
+            //  It is also likely possible to read large parts of the sector instead of the whole
+            //  sector if code below is not parallelized, but logic will become even more
+            //  convoluted, so for now it is not done.
+            #[cfg(windows)]
+            let sector_bytes = {
+                let mut sector_bytes = vec![0u8; crate::sector::sector_size(pieces_in_sector)];
+                sector.read_at(&mut sector_bytes, 0)?;
+                sector_bytes
+            };
             read_chunks_inputs.into_par_iter().flatten().try_for_each(
                 |(maybe_record_chunk, chunk_location, encoded_chunk_used, s_bucket)| {
                     let mut record_chunk = [0; Scalar::FULL_BYTES];
+                    #[cfg(windows)]
+                    record_chunk.copy_from_slice(
+                        &sector_bytes[sector_contents_map_size as usize
+                            + chunk_location as usize * Scalar::FULL_BYTES..][..Scalar::FULL_BYTES],
+                    );
+                    #[cfg(not(windows))]
                     sector
                         .read_at(
                             &mut record_chunk,