fixup incorrect assumption

Author: glbrntt

Sources/GRPC/GRPCClientStateMachine.swift

@@ -521,14 +521,14 @@ extension GRPCClientStateMachine.State {
       "user-agent": "grpc-swift-nio",  //  TODO: Add a more specific user-agent.
     ]
 
-    // Message level encoding.
+    // Request encoding.
     if let outbound = compression.outbound {
       headers.add(name: GRPCHeaderName.encoding, value: outbound.name)
+    }
 
-      // Only send 'accept-encoding' if inbound and outbound are enabled.
-      if !compression.inbound.isEmpty {
-        headers.add(name: GRPCHeaderName.acceptEncoding, value: compression.acceptEncodingHeader)
-      }
+    // Response encoding.
+    if !compression.inbound.isEmpty {
+      headers.add(name: GRPCHeaderName.acceptEncoding, value: compression.acceptEncodingHeader)
     }
 
     // Add the timeout header, if a timeout was specified.

Tests/GRPCTests/GRPCClientStateMachineTests.swift

@@ -707,9 +707,7 @@ extension GRPCClientStateMachineTests {
       encoding: .init(forRequests: nil, acceptableForResponses: [.identity, .gzip])
     )).assertSuccess { headers in
       XCTAssertFalse(headers.contains(name: "grpc-encoding"))
-      // If we don't set request encoding then we shouldn't set the accept-encoding header. (The
-      // compression asymmetry can be achieved by setting the request compression to '.identity'.)
-      XCTAssertFalse(headers.contains(name: "grpc-accept-encoding"))
+      XCTAssertTrue(headers.contains(name: "grpc-accept-encoding"))
     }
   }