Add configuration of multipathServiceType in NIOTSConnectionBootstrap

Sources/NIOTransportServices/NIOTSConnectionBootstrap.swift

@@ -154,6 +154,12 @@ public final class NIOTSConnectionBootstrap {
         return self
     }
 
+    /// Specifies a type of Multipath service to use for this connection, instead of the default
+    /// service type for the event loop.
+    public func withMultipath(_ type: NWParameters.MultipathServiceType) -> Self {
+        self.channelOption(NIOTSChannelOptions.multipathServiceType, value: type)
+    }
+
     /// Specify the `host` and `port` to connect to for the TCP `Channel` that will be established.
     ///
     /// - parameters:

Sources/NIOTransportServices/NIOTSListenerBootstrap.swift

@@ -235,6 +235,16 @@ public final class NIOTSListenerBootstrap {
         return self
     }
 
+    /// Specifies a type of Multipath service to use for this listener, instead of the default
+    /// service type for the event loop.
+    ///
+    /// Warning: Multipath service doesn't seem supported on the listener side yet, as
+    /// described on https://www.mptcp.dev/macOS.html. Note that enabling Multipath
+    /// may then generate unexpected errors, use this function with caution.
+    public func withMultipath(_ type: NWParameters.MultipathServiceType) -> Self {
+        self.serverChannelOption(NIOTSChannelOptions.multipathServiceType, value: type)
+    }
+
     /// Bind the `NIOTSListenerChannel` to `host` and `port`.
     ///
     /// - parameters:

Tests/NIOTransportServicesTests/NIOTSBootstrapTests.swift

@@ -336,6 +336,25 @@ final class NIOTSBootstrapTests: XCTestCase {
             try? connectionChannel?.close().wait()
         }
     }
+
+    func testBootstrapsMultipath() throws {
+        let group = NIOTSEventLoopGroup()
+        defer {
+            try! group.syncShutdownGracefully()
+        }
+
+        let listenerBootstrap = NIOTSListenerBootstrap(group: group).withMultipath(.handover)
+        let connectionBootstrap = NIOTSConnectionBootstrap(group: group).withMultipath(.handover)
+
+        let listenerChannel: Channel = try listenerBootstrap.bind(host: "localhost", port: 0).wait()
+        let connectionChannel: Channel = try connectionBootstrap.connect(to: listenerChannel.localAddress!).wait()
+        defer{
+            try? listenerChannel.close().wait()
+            try? connectionChannel.close().wait()
+        }
+        XCTAssertEqual(try listenerChannel.getOption(NIOTSChannelOptions.multipathServiceType).wait(), .handover)
+        XCTAssertEqual(try connectionChannel.getOption(NIOTSChannelOptions.multipathServiceType).wait(), .handover)
+    }
 }
 
 extension Channel {