diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3d04693..ee407dd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
+## 3.0.10
+  - Deps: unpin rufus scheduler [#20](https://github.com/logstash-plugins/logstash-output-cloudwatch/pull/20)
+  - Fix: an old undefined method error which would surface with load (as queue fills up) 
+
 ## 3.0.9
-- Fix: dropped usage of SHUTDOWN event deprecated since Logstash 5.0 [#18](https://github.com/logstash-plugins/logstash-output-cloudwatch/pull/18)
+  - Fix: dropped usage of SHUTDOWN event deprecated since Logstash 5.0 [#18](https://github.com/logstash-plugins/logstash-output-cloudwatch/pull/18)
 
 ## 3.0.8
   - Docs: Set the default_codec doc attribute.
diff --git a/lib/logstash/outputs/cloudwatch.rb b/lib/logstash/outputs/cloudwatch.rb
index f59532d..307b740 100644
--- a/lib/logstash/outputs/cloudwatch.rb
+++ b/lib/logstash/outputs/cloudwatch.rb
@@ -3,6 +3,8 @@
 require "logstash/namespace"
 require "logstash/plugin_mixins/aws_config"
 
+require "rufus/scheduler"
+
 # This output lets you aggregate and send metric data to AWS CloudWatch
 #
 # ==== Summary:
@@ -154,28 +156,34 @@ class LogStash::Outputs::CloudWatch < LogStash::Outputs::Base
   #     `add_field => [ "CW_dimensions", "prod" ]`
   config :field_dimensions, :validate => :string, :default => "CW_dimensions"
 
+  attr_reader :event_queue
+
   public
   def register
     require "thread"
-    require "rufus/scheduler"
     require "aws-sdk"
 
     @cw = Aws::CloudWatch::Client.new(aws_options_hash)
 
     @event_queue = SizedQueue.new(@queue_size)
     @scheduler = Rufus::Scheduler.new
-    @job = @scheduler.every @timeframe do
+    @job = @scheduler.schedule_every @timeframe do
       @logger.debug("Scheduler Activated")
       publish(aggregate({}))
     end
   end # def register
 
+  # Rufus::Scheduler >= 3.4 moved the Time impl into a gem EoTime = ::EtOrbi::EoTime`
+  # Rufus::Scheduler 3.1 - 3.3 using it's own Time impl `Rufus::Scheduler::ZoTime`
+  RufusTimeImpl = defined?(Rufus::Scheduler::EoTime) ? Rufus::Scheduler::EoTime :
+                      (defined?(Rufus::Scheduler::ZoTime) ? Rufus::Scheduler::ZoTime : ::Time)
+
   public
   def receive(event)
     return unless (event.get(@field_metricname) || @metricname)
 
     if (@event_queue.length >= @event_queue.max)
-      @job.trigger
+      @job.trigger RufusTimeImpl.now
       @logger.warn("Posted to AWS CloudWatch ahead of schedule.  If you see this often, consider increasing the cloudwatch queue_size option.")
     end
 
diff --git a/logstash-output-cloudwatch.gemspec b/logstash-output-cloudwatch.gemspec
index 15c3e9a..e61c535 100644
--- a/logstash-output-cloudwatch.gemspec
+++ b/logstash-output-cloudwatch.gemspec
@@ -1,7 +1,7 @@
 Gem::Specification.new do |s|
 
   s.name            = 'logstash-output-cloudwatch'
-  s.version         = '3.0.9'
+  s.version         = '3.0.10'
   s.licenses        = ['Apache License (2.0)']
   s.summary         = "Aggregates and sends metric data to AWS CloudWatch"
   s.description     = "This gem is a Logstash plugin required to be installed on top of the Logstash core pipeline using $LS_HOME/bin/logstash-plugin install gemname. This gem is not a stand-alone program"
@@ -22,7 +22,7 @@ Gem::Specification.new do |s|
   # Gem dependencies
   s.add_runtime_dependency "logstash-core-plugin-api", ">= 1.60", "<= 2.99"
   s.add_runtime_dependency 'logstash-mixin-aws', '>= 1.0.0'
-  s.add_runtime_dependency 'rufus-scheduler', [ '~> 3.0.9' ]
+  s.add_runtime_dependency 'rufus-scheduler', '>= 3.0.9'
 
   s.add_development_dependency 'logstash-devutils'
 end
diff --git a/spec/outputs/cloudwatch_spec.rb b/spec/outputs/cloudwatch_spec.rb
index b98420c..96ab79b 100644
--- a/spec/outputs/cloudwatch_spec.rb
+++ b/spec/outputs/cloudwatch_spec.rb
@@ -1,18 +1,38 @@
 require "logstash/devutils/rspec/spec_helper"
-require "logstash/plugin"
-require "logstash/json"
+require "logstash/outputs/cloudwatch"
 
 describe "outputs/cloudwatch" do
   
+  let(:config) { { 'metricname' => 'foo' } }
 
-  output = LogStash::Plugin.lookup("output", "cloudwatch").new
+  subject(:plugin) { LogStash::Outputs::CloudWatch.new(config) }
 
   it "should register" do
-    expect {output.register}.to_not raise_error
+    expect { plugin.register }.to_not raise_error
   end
 
   it "should respond correctly to a receive call" do
+    plugin.register
     event = LogStash::Event.new
-    expect { output.receive(event) }.to_not raise_error
+    expect { plugin.receive(event) }.to_not raise_error
+  end
+
+  context 'with queue_size' do
+
+    let(:queue_size) { 100 }
+
+    let(:config) { super().merge('queue_size' => queue_size) }
+
+    it "triggers job ahead of time" do
+      plugin.register
+      event_queue = plugin.event_queue
+      allow( event_queue ).to receive(:length).and_return queue_size # emulate full queue
+      expect( plugin ).to receive(:publish)
+
+      event = LogStash::Event.new
+      plugin.receive(event)
+      sleep 1.0 # allow scheduler to kick in
+    end
+
   end
 end