Each chunked upload allocated a fresh chunk-sized buffer (48 MiB by
default), so bulk transfers of many files churned allocations and GC.
Buffer chunks with multipart.NewRW instead so chunk memory is reused
across uploads and is part of rclone's central memory management. The
pool.RW is seekable, so the existing IncorrectOffset recovery which
skips already-received bytes on retry carries over unchanged, and the
"chunk received OK" check now compares against the bytes actually
buffered so a short final chunk is recognised too.
The Dropbox SDK wraps the request body in io.NopCloser, so the transport
never closes the pool buffer. The upload loop closes it after every
chunk, on error paths included.
The FsPutRetry integration test covers the retry of a failed upload
request and checks the buffers are returned to the pool.
Nick Craig-Wood
738eadf8df