Resume partial download on network failure #4448
Description
Download failures always require downloading files from scratch,
which is simply unacceptable in poor network environments
Is it possible to avoid repeatedly downloading data that has already been partially downloaded
info: syncing channel updates for 'nightly-aarch64-unknown-linux-gnu'
Total: 1.0 MiB Speed: 81.4 KiB/s Elapsed: 1m 13s
info: latest update on 2025-08-17, rust version 1.91.0-nightly (2e2642e64 2025-08-16)
info: downloading component 'cargo'
info: downloading component 'clippy'
info: downloading component 'rust-docs'
info: downloading component 'rust-std'
info: downloading component 'rustc'
230.5 KiB / 59.1 MiB ( 0 %) 29.6 KiB/s in 57s ETA: 33m 57s
info: retrying download for 'https://rsproxy.cn/dist/2025-08-17/rustc-nightly-aarch64-unknown-linux-gnu.tar.xz'
9.3 MiB / 59.1 MiB ( 16 %) 28.8 KiB/s in 12m 17s ETA: 29m 32s
info: retrying download for 'https://rsproxy.cn/dist/2025-08-17/rustc-nightly-aarch64-unknown-linux-gnu.tar.xz'
58.4 MiB / 59.1 MiB ( 99 %) 49.6 KiB/s in 26m 53s ETA: 15s
info: retrying download for 'https://rsproxy.cn/dist/2025-08-17/rustc-nightly-aarch64-unknown-linux-gnu.tar.xz'
58.5 MiB / 59.1 MiB ( 99 %) 81.6 KiB/s in 26m 14s ETA: 8s
info: retrying download for 'https://rsproxy.cn/dist/2025-08-17/rustc-nightly-aarch64-unknown-linux-gnu.tar.xz'
error: component download failed for rustc-aarch64-unknown-linux-gnu: could not download file from 'https://rsproxy.cn/dist/2025-08-17/rustc-nightly-aarch64-unknown-linux-gnu.tar.xz' to '/home/lrne/.rustup/downloads/3ad6539cfc893725b69f59bb2e72a4ff71c1719186b3ea48eb3c9da56c2a8405.partial': error decoding response body: request or response body error: error reading a body from connection: connection reset
info: syncing channel updates for 'nightly-aarch64-unknown-linux-gnu'
Total: 1.0 MiB Speed: 76.6 KiB/s Elapsed: 14s
info: latest update on 2025-08-17, rust version 1.91.0-nightly (2e2642e64 2025-08-16)
info: downloading component 'cargo'
info: downloading component 'clippy'
info: downloading component 'rust-docs'
info: downloading component 'rust-std'
info: downloading component 'rustc'
10.2 MiB / 59.1 MiB ( 17 %) 75.2 KiB/s in 3m 57s ETA: 11m 6s