patch async-compression to compress responses in streaming

Cargo.toml

@@ -32,3 +32,11 @@ members = [
 # debug = false
 strip = "debuginfo"
 incremental = false
+
+# Temporary patch to async-compression
+# It is used by tower-http's CompressionLayer. The compression code was not handling
+# the Poll::Pending result from the underlying stream, so it was accumulating the
+# entire compressed response in memory before sending it, which creates issues with
+# deferred responses getting received too late
+[patch.crates-io]
+async-compression = { git = 'https://github.com/geal/async-compression', branch = 'encoder-flush' }

NEXT_CHANGELOG.md

@@ -170,6 +170,14 @@ next chunk to see the delimiter.
 
 By [@Geal](https://github.com/Geal) in https://github.com/apollographql/router/pull/1596
 
+### Patch async-compression to compress responses in streaming ([PR #1604](https://github.com/apollographql/router/issues/1604))
+
+async-compression is a dependency used for response compression. Its implementation accumulates the entire compressed response
+in memory before sending it, which creates problems for deferred responses, where we want the responses to come as soon as
+possible, and not all at once after a while.
+
+By [@Geal](https://github.com/Geal) in https://github.com/apollographql/router/pull/1604
+
 ## 🛠 Maintenance
 
 ### Depend on published `router-bridge` ([PR #1613](https://github.com/apollographql/router/issues/1613))