diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index 6b9a3c0..78c3d26 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -32,10 +32,10 @@ jobs:
         run: cargo install cross --git https://github.com/cross-rs/cross --rev 6d097fb
 
       - name: Build
-        run: cross build --target ${{ matrix.target }} -vv
+        run: cross build --target ${{ matrix.target }} --release -vv
 
       - name: Test
-        run: cross test --target ${{ matrix.target }} -vv
+        run: cross test --target ${{ matrix.target }} --release -vv
 
   test-wasm32-emscripten:
     runs-on: ubuntu-latest
@@ -60,7 +60,7 @@ jobs:
         uses: mymindstorm/setup-emsdk@v14
 
       - name: Build
-        run: cargo build --target wasm32-unknown-emscripten --no-default-features --features ${{ matrix.build }}
+        run: cargo build --release --target wasm32-unknown-emscripten --no-default-features --features ${{ matrix.build }}
 
   test-native:
     runs-on: ${{ matrix.os }}
@@ -97,9 +97,9 @@ jobs:
         run: brew install automake autoconf coreutils libtool nasm
 
       - name: Test (shared)
-        run: cargo test --no-default-features --features shared --lib -vv
+        run: cargo test --release --no-default-features --features shared --lib -vv
 
       - name: Test (static)
         run: |
           cargo clean  # ensure we're starting fresh, no funny business
-          cargo test --no-default-features --features static -vv
+          cargo test --release --no-default-features --features static -vv
diff --git a/src/igzip/read.rs b/src/igzip/read.rs
index 75e3744..cc93165 100644
--- a/src/igzip/read.rs
+++ b/src/igzip/read.rs
@@ -64,26 +64,25 @@ impl<R: io::Read> io::Read for Encoder<R> {
     #[inline]
     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
         // Check if there is data left in out_buf, otherwise refill; if end state, return 0
-        if self.stream.stream.internal_state.state != isal::isal_zstate_state_ZSTATE_END {
-            if self.stream.stream.avail_in == 0 {
-                // Read out next buf len worth to compress; filling intermediate out_buf
-                self.stream.stream.avail_in = self.inner.read(&mut self.in_buf)? as _;
-                self.stream.stream.next_in = self.in_buf.as_mut_ptr();
-                self.stream.stream.end_of_stream =
-                    (self.stream.stream.avail_in < self.in_buf.len() as _) as _;
-            }
+        if self.stream.stream.internal_state.state != isal::isal_zstate_state_ZSTATE_END
+            && (self.stream.stream.avail_in == 0
+                || self.stream.stream.internal_state.state
+                    != isal::isal_zstate_state_ZSTATE_TMP_FLUSH_ICF_BUFFER)
+        {
+            // Read out next buf len worth to compress; filling intermediate out_buf
+            self.stream.stream.avail_in = self.inner.read(&mut self.in_buf)? as _;
+            self.stream.stream.next_in = self.in_buf.as_mut_ptr();
+            self.stream.stream.end_of_stream =
+                (self.stream.stream.avail_in < self.in_buf.len() as _) as _;
+        }
 
-            // compress this chunk into out_buf
-            self.stream.stream.avail_out = buf.len() as _;
-            self.stream.stream.next_out = buf.as_mut_ptr();
+        self.stream.stream.avail_out = buf.len() as _;
+        self.stream.stream.next_out = buf.as_mut_ptr();
 
-            self.stream.deflate()?;
+        self.stream.deflate()?;
 
-            let nbytes = buf.len() - self.stream.stream.avail_out as usize;
-            Ok(nbytes)
-        } else {
-            Ok(0)
-        }
+        let nbytes = buf.len() - self.stream.stream.avail_out as usize;
+        Ok(nbytes)
     }
 }