Compression support for single-file publish

[Genbox]

As mentioned in the original single-file issue and in bottom of the single-file design doc, compression is something that is worth taking a look at.

A lot of applications would benefit from smaller executables. Not only is the user experience better as a smaller file means smaller download time, but it also benefits the data transfer costs.

Trimming has helped a lot, and the new .NET 5.0 single-file publish is a great improvement on what we had in .NET Core 3.1. However, a simple Hello World application is still 19 MB as a single-file executable. If I compress it with 7Z LZMA it is 6 MB.

A first step could be to implement deflate compression in the GenerateBundle Msbuild step, and then have the host decompress it in a streaming fashion from the bundle directly. This would incur a small overhead in startup time, so maybe it should have a switch - something like /p:SingleFileCompression=true.

It would be nice to have the compression algorithm pluggable, so if we ever get to have LZMA (see #1542), we can get even better compression ratio.

[ghost]

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Issue meta data

Issue content:	As mentioned in the [original single-file issue](https://github.com//issues/36590#issuecomment-696409066) and in bottom of the [single-file design doc](https://github.com/dotnet/designs/blob/main/accepted/2020/single-file/design.md), compression is something that is worth taking a look at. A lot of applications would benefit from smaller executables. Not only is the user experience better as a smaller file means smaller download time, but it also benefits the data transfer costs. Trimming has helped a lot, and the new .NET 5.0 single-file publish is a great improvement on what we had in .NET Core 3.1. However, a simple Hello World application is still 19 MB as a single-file executable. If I compress it with 7Z LZMA it is 6 MB. A first step could be to implement deflate compression in the GenerateBundle Msbuild step, and then have the host decompress it in a streaming fashion from the bundle directly. This would incur a small overhead in startup time, so maybe it should have a switch - something like /p:SingleFileCompression=true. It would be nice to have the compression algorithm pluggable, so if we ever get to have LZMA (see #1542), we can get even better compression ratio.
Issue author:	Genbox
Assignees:	-
Milestone:	-

[tmoonlight]

we need this function.

[NN---]

#49855

[agocke]

This has been implemented as an optional switch for .NET 6.