Re-add comments

message/store_sqlite.go

@@ -135,6 +135,11 @@ func NewNopStore() (Store, error) {
 }
 
 // createMemoryFilename creates a unique memory filename to use for the SQLite backend.
+// From mattn/go-sqlite3: "Each connection to ":memory:" opens a brand new in-memory
+// sql database, so if the stdlib's sql engine happens to open another connection and
+// you've only specified ":memory:", that connection will see a brand new database.
+// A workaround is to use "file::memory:?cache=shared" (or "file:foobar?mode=memory&cache=shared").
+// Every connection to this string will point to the same in-memory database."
 func createMemoryFilename() string {
 	return fmt.Sprintf("file:%s?mode=memory&cache=shared", util.RandomString(10))
 }