Use the same busy_handler function as will be in the sqlite3-ruby gem

See sparklemotion/sqlite3-ruby#456

lib/enhanced_sqlite3/adapter.rb

@@ -55,22 +55,17 @@ def configure_connection
     def configure_busy_handler_timeout
       return unless @config.key?(:timeout)
 
-      timeout = self.class.type_cast_config_to_integer(@config[:timeout])
-      timeout_seconds = timeout.fdiv(1000)
-      retry_interval = 6e-5 # 60 microseconds
+      timeout_milliseconds = self.class.type_cast_config_to_integer(@config[:timeout])
+      timeout_seconds = timeout_milliseconds.fdiv(1000)
 
       @raw_connection.busy_handler do |count|
-        timed_out = false
-        # keep track of elapsed time every 100 iterations (to lower load)
-        if (count % 100).zero?
-          # fail if we exceed the timeout value (captured from the timeout config option, converted to seconds)
-          timed_out = (count * retry_interval) > timeout_seconds
-        end
-        if timed_out
-          false # this will cause the BusyException to be raised
+        now = Process.clock_gettime(Process::CLOCK_MONOTONIC)
+        if count.zero?
+          @timeout_deadline = now + timeout_seconds
+        elsif now > @timeout_deadline
+          next false
         else
-          sleep(retry_interval)
-          true
+          sleep(0.001)
         end
       end
     end