Add Message#strip methods to strip whitespace from messages

These mehods work very similar to their String equivalents.

lib/rackstash/message.rb

@@ -132,6 +132,24 @@ module Rackstash
       copy_with(message.freeze)
     end
 
+    # @return [Message] Returns a copy of `self` with leading whitespace
+    #   removed on the `message`.
+    def lstrip
+      copy_with(@message.lstrip.freeze)
+    end
+
+    # @return [Message] Returns a copy of `self` with trailing whitespace
+    #   removed on the `message`.
+    def rstrip
+      copy_with(@message.rstrip.freeze)
+    end
+
+    # @return [Message] Returns a copy of `self` with leading and trailing
+    #   whitespace removed on the `message`.
+    def strip
+      copy_with(@message.strip.freeze)
+    end
+
     # @return [String] the human readable label for the {#severity}.
     # @see Rackstash.severity_label
     def severity_label

spec/rackstash/message_spec.rb

@@ -13,7 +13,8 @@ require 'rackstash/message'
 
 describe Rackstash::Message do
   let(:message_args) { {} }
-  let(:message) { described_class.new 'message', **message_args }
+  let(:msg) { 'message' }
+  let(:message) { described_class.new msg, **message_args }
 
   describe '#initialize' do
     it 'encodes the message as UTF-8' do
@@ -118,6 +119,48 @@ describe Rackstash::Message do
     end
   end
 
+  describe '#lstrip' do
+    let(:msg) { "\t \r\t\nmy \tmessage\r\n \t" }
+
+    it 'returns a new Message' do
+      expect(message.lstrip).to be_instance_of(described_class)
+      expect(message.lstrip).not_to equal message
+    end
+
+    it 'strips leading whitespace from the message' do
+      msg = "\t \r\t\nmy \tmessage\r\n \t"
+      expect(message.lstrip.to_s).to eql "my \tmessage\r\n \t"
+    end
+  end
+
+  describe '#rstrip' do
+    let(:msg) { "\t \r\t\nmy \tmessage\r\n \t" }
+
+    it 'returns a new Message' do
+      expect(message.rstrip).to be_instance_of(described_class)
+      expect(message.rstrip).not_to equal message
+    end
+
+    it 'strips trailing whitespace from the message' do
+      expect(message.rstrip.to_s).to eql "\t \r\t\nmy \tmessage"
+    end
+  end
+
+  describe '#strip' do
+    let(:msg) { "\t \r\t\nmy \tmessage\r\n \t" }
+
+    it 'returns a new Message' do
+      expect(message.strip).to be_instance_of(described_class)
+      expect(message.strip).not_to equal message
+    end
+
+    it 'strips the message' do
+      msg = "\t \r\t\nmy \tmessage\r\n \t"
+      expect(message.strip.to_s).to eql "my \tmessage"
+    end
+  end
+
+
   describe '#message' do
     it 'is aliased to to_str' do
       message = described_class.new('hello world')