Run tests on Windows.

.github/workflows/test.yaml

@@ -35,6 +35,9 @@ jobs:
           - os: ubuntu
             ruby: head
             experimental: true
+          - os: windows
+            ruby: head
+            experimental: true
 
     steps:
     - uses: actions/checkout@v3

lib/async/scheduler.rb

@@ -23,6 +23,10 @@ def self.supported?
 			true
 		end
 
+		def self.windows?
+			::RUBY_PLATFORM =~ /mswin|mingw|cygwin/
+		end
+
 		def initialize(parent = nil, selector: nil)
 			super(parent)
 
@@ -167,12 +171,26 @@ def io_wait(io, events, timeout = nil)
 		end
 
 		if ::IO::Event::Support.buffer?
-			def io_read(io, buffer, length, offset = 0)
-				@selector.io_read(Fiber.current, io, buffer, length, offset)
-			end
-
-			def io_write(io, buffer, length, offset = 0)
-				@selector.io_write(Fiber.current, io, buffer, length, offset)
+			if Scheduler.windows?
+				def io_read(io, buffer, length, offset = 0)
+					Thread.new do
+						buffer.read(io, length, offset)
+					end.value
+				end
+
+				def io_write(io, buffer, length, offset = 0)
+					Thread.new do
+						buffer.write(io, length, offset)
+					end.value
+				end
+			else
+				def io_read(io, buffer, length, offset = 0)
+					@selector.io_read(Fiber.current, io, buffer, length, offset)
+				end
+
+				def io_write(io, buffer, length, offset = 0)
+					@selector.io_write(Fiber.current, io, buffer, length, offset)
+				end
 			end
 		end