diff --git a/spec/helpers_spec.cr b/spec/helpers_spec.cr
index df24ec3..e6de9d5 100644
--- a/spec/helpers_spec.cr
+++ b/spec/helpers_spec.cr
@@ -109,5 +109,17 @@ describe "Macros" do
       response.headers["Content-Type"].should eq("image/jpeg")
       response.headers["Content-Length"].should eq("20")
     end
+
+    it "sends file with binary stream" do
+      get "/" do |env|
+        send_file env, "Serdar".to_slice
+      end
+
+      request = HTTP::Request.new("GET", "/")
+      response = call_request_on_app(request)
+      response.status_code.should eq(200)
+      response.headers["Content-Type"].should eq("application/octet-stream")
+      response.headers["Content-Length"].should eq("6")
+    end
   end
 end
diff --git a/src/kemal/helpers/helpers.cr b/src/kemal/helpers/helpers.cr
index cc32386..6dba009 100644
--- a/src/kemal/helpers/helpers.cr
+++ b/src/kemal/helpers/helpers.cr
@@ -50,7 +50,7 @@ end
 #   send_file env, "./path/to/file", "image/jpeg"
 def send_file(env, path : String, mime_type : String? = nil)
   file_path = File.expand_path(path, Dir.current)
-  mime_type = "application/octet-stream" unless mime_type
+  mime_type ||= "application/octet-stream" 
   env.response.content_type = mime_type
   env.response.content_length = File.size(file_path)
   File.open(file_path) do |file|
@@ -65,11 +65,9 @@ end
 # Optionally you can override the mime_type
 #
 #   send_file env, data_slice, "image/jpeg"
-
 def send_file(env, data : Slice(UInt8), mime_type : String? = nil)
   mime_type ||= "application/octet-stream"
-
   env.response.content_type = mime_type
   env.response.content_length = data.bytesize
   env.response.write data
-end
+end
\ No newline at end of file