reduce memory usage (#1133)

Large memory usage comes from:

Mimalloc hold large thread cache, causing abort 13M+ usage.
QUIC endpoint occupy 3M when GRO is enabled.
Smoltcp 64 tcp listener use 2MB.

.github/workflows/install_rust.sh

@@ -29,8 +29,8 @@ fi
 
 # see https://github.com/rust-lang/rustup/issues/3709
 rustup set auto-self-update disable
-rustup install 1.86
-rustup default 1.86
+rustup install 1.87
+rustup default 1.87
 
 # mips/mipsel cannot add target from rustup, need compile by ourselves
 if [[ $OS =~ ^ubuntu.*$ && $TARGET =~ ^mips.*$ ]]; then