diff --git a/Tests/NIOPosixTests/AcceptBackoffHandlerTest.swift b/Tests/NIOPosixTests/AcceptBackoffHandlerTest.swift
index fa66c5300f1..f249d0d15ed 100644
--- a/Tests/NIOPosixTests/AcceptBackoffHandlerTest.swift
+++ b/Tests/NIOPosixTests/AcceptBackoffHandlerTest.swift
@@ -20,7 +20,11 @@ import XCTest
 
 @testable import NIOPosix
 
-public final class AcceptBackoffHandlerTest: XCTestCase {
+final class AcceptBackoffHandlerTest: XCTestCase {
+    @Sendable
+    static func defaultBackoffProvider(error: IOError) -> TimeAmount? {
+        AcceptBackoffHandler.defaultBackoffProvider(error: error)
+    }
 
     private let acceptHandlerName = "AcceptBackoffHandler"
 
@@ -46,13 +50,17 @@ public final class AcceptBackoffHandlerTest: XCTestCase {
 
     private func assertBackoffRead(error: Int32) throws {
         let group = MultiThreadedEventLoopGroup(numberOfThreads: 1)
+        let loop = group.next() as! SelectableEventLoop
         defer {
             XCTAssertNoThrow(try group.syncShutdownGracefully())
         }
 
-        let readCountHandler = ReadCountHandler()
+        // Only used from EL
+        let readCountHandler = try! loop.submit {
+            NIOLoopBound(ReadCountHandler(), eventLoop: loop)
+        }.wait()
         let serverChannel = try setupChannel(
-            group: group,
+            eventLoop: loop,
             readCountHandler: readCountHandler,
             backoffProvider: { _ in .milliseconds(100) },
             errors: [error]
@@ -62,7 +70,7 @@ public final class AcceptBackoffHandlerTest: XCTestCase {
             try serverChannel.eventLoop.submit {
                 serverChannel.readable()
                 serverChannel.read()
-                return readCountHandler.readCount
+                return readCountHandler.value.readCount
             }.wait()
         )
 
@@ -70,7 +78,7 @@ public final class AcceptBackoffHandlerTest: XCTestCase {
         XCTAssertEqual(
             1,
             try serverChannel.eventLoop.scheduleTask(in: .milliseconds(100)) {
-                readCountHandler.readCount
+                readCountHandler.value.readCount
             }.futureResult.wait()
         )
 
@@ -79,7 +87,7 @@ public final class AcceptBackoffHandlerTest: XCTestCase {
             2,
             try serverChannel.eventLoop.submit {
                 serverChannel.read()
-                return readCountHandler.readCount
+                return readCountHandler.value.readCount
             }.wait()
         )
 
@@ -96,13 +104,16 @@ public final class AcceptBackoffHandlerTest: XCTestCase {
 
     private func assertRemoval(read: Bool) throws {
         let group = MultiThreadedEventLoopGroup(numberOfThreads: 1)
+        let loop = group.next() as! SelectableEventLoop
         defer {
             XCTAssertNoThrow(try group.syncShutdownGracefully())
         }
 
-        let readCountHandler = ReadCountHandler()
+        let readCountHandler = try! loop.submit {
+            NIOLoopBound(ReadCountHandler(), eventLoop: loop)
+        }.wait()
         let serverChannel = try setupChannel(
-            group: group,
+            eventLoop: loop,
             readCountHandler: readCountHandler,
             backoffProvider: { err in
                 .hours(1)
@@ -116,7 +127,7 @@ public final class AcceptBackoffHandlerTest: XCTestCase {
                 if read {
                     serverChannel.read()
                 }
-                return readCountHandler.readCount
+                return readCountHandler.value.readCount
             }.wait()
         )
 
@@ -127,7 +138,7 @@ public final class AcceptBackoffHandlerTest: XCTestCase {
             XCTAssertEqual(
                 1,
                 try serverChannel.eventLoop.submit {
-                    readCountHandler.readCount
+                    readCountHandler.value.readCount
                 }.wait()
             )
         } else {
@@ -135,7 +146,7 @@ public final class AcceptBackoffHandlerTest: XCTestCase {
             XCTAssertEqual(
                 0,
                 try serverChannel.eventLoop.submit {
-                    readCountHandler.readCount
+                    readCountHandler.value.readCount
                 }.wait()
             )
         }
@@ -144,13 +155,16 @@ public final class AcceptBackoffHandlerTest: XCTestCase {
 
     public func testNotScheduleReadIfAlreadyScheduled() throws {
         let group = MultiThreadedEventLoopGroup(numberOfThreads: 1)
+        let loop = group.next() as! SelectableEventLoop
         defer {
             XCTAssertNoThrow(try group.syncShutdownGracefully())
         }
 
-        let readCountHandler = ReadCountHandler()
+        let readCountHandler = try! loop.submit {
+            NIOLoopBound(ReadCountHandler(), eventLoop: loop)
+        }.wait()
         let serverChannel = try setupChannel(
-            group: group,
+            eventLoop: loop,
             readCountHandler: readCountHandler,
             backoffProvider: { err in
                 .milliseconds(10)
@@ -163,7 +177,7 @@ public final class AcceptBackoffHandlerTest: XCTestCase {
                 serverChannel.readable()
                 serverChannel.read()
                 serverChannel.read()
-                return readCountHandler.readCount
+                return readCountHandler.value.readCount
             }.wait()
         )
 
@@ -172,7 +186,7 @@ public final class AcceptBackoffHandlerTest: XCTestCase {
         XCTAssertEqual(
             1,
             try serverChannel.eventLoop.scheduleTask(in: .milliseconds(500)) {
-                readCountHandler.readCount
+                readCountHandler.value.readCount
             }.futureResult.wait()
         )
 
@@ -181,7 +195,7 @@ public final class AcceptBackoffHandlerTest: XCTestCase {
             2,
             try serverChannel.eventLoop.submit {
                 serverChannel.read()
-                return readCountHandler.readCount
+                return readCountHandler.value.readCount
             }.wait()
         )
 
@@ -190,6 +204,7 @@ public final class AcceptBackoffHandlerTest: XCTestCase {
 
     public func testChannelInactiveCancelScheduled() throws {
         let group = MultiThreadedEventLoopGroup(numberOfThreads: 1)
+        let loop = group.next() as! SelectableEventLoop
         defer {
             XCTAssertNoThrow(try group.syncShutdownGracefully())
         }
@@ -212,9 +227,12 @@ public final class AcceptBackoffHandlerTest: XCTestCase {
             }
         }
 
-        let readCountHandler = ReadCountHandler()
+        let readCountHandler = try! loop.submit {
+            NIOLoopBound(ReadCountHandler(), eventLoop: loop)
+        }.wait()
+
         let serverChannel = try setupChannel(
-            group: group,
+            eventLoop: loop,
             readCountHandler: readCountHandler,
             backoffProvider: { err in
                 .milliseconds(10)
@@ -222,8 +240,12 @@ public final class AcceptBackoffHandlerTest: XCTestCase {
             errors: [ENFILE]
         )
 
-        let inactiveVerificationHandler = InactiveVerificationHandler(promise: serverChannel.eventLoop.makePromise())
-        XCTAssertNoThrow(try serverChannel.pipeline.addHandler(inactiveVerificationHandler).wait())
+        let inactivePromise = serverChannel.eventLoop.makePromise(of: Void.self)
+        let configured = loop.submit {
+            let inactiveVerificationHandler = InactiveVerificationHandler(promise: inactivePromise)
+            try serverChannel.pipeline.syncOperations.addHandler(inactiveVerificationHandler)
+        }
+        XCTAssertNoThrow(try configured.wait())
 
         XCTAssertEqual(
             0,
@@ -232,7 +254,7 @@ public final class AcceptBackoffHandlerTest: XCTestCase {
                 serverChannel.read()
                 // Close the channel, this should also take care of cancel the scheduled read.
                 serverChannel.close(promise: nil)
-                return readCountHandler.readCount
+                return readCountHandler.value.readCount
             }.wait()
         )
 
@@ -240,24 +262,27 @@ public final class AcceptBackoffHandlerTest: XCTestCase {
         XCTAssertEqual(
             0,
             try serverChannel.eventLoop.scheduleTask(in: .milliseconds(500)) {
-                readCountHandler.readCount
+                readCountHandler.value.readCount
             }.futureResult.wait()
         )
 
-        XCTAssertNoThrow(try inactiveVerificationHandler.waitForInactive())
+        XCTAssertNoThrow(try inactivePromise.futureResult.wait())
     }
 
     public func testSecondErrorUpdateScheduledRead() throws {
         let group = MultiThreadedEventLoopGroup(numberOfThreads: 1)
+        let loop = group.next() as! SelectableEventLoop
         defer {
             XCTAssertNoThrow(try group.syncShutdownGracefully())
         }
 
-        let readCountHandler = ReadCountHandler()
+        let readCountHandler = try! loop.submit {
+            NIOLoopBound(ReadCountHandler(), eventLoop: loop)
+        }.wait()
 
         let backoffProviderCalled = ManagedAtomic(0)
         let serverChannel = try setupChannel(
-            group: group,
+            eventLoop: loop,
             readCountHandler: readCountHandler,
             backoffProvider: { err in
                 if backoffProviderCalled.loadThenWrappingIncrement(ordering: .relaxed) == 0 {
@@ -273,7 +298,7 @@ public final class AcceptBackoffHandlerTest: XCTestCase {
             try serverChannel.eventLoop.submit {
                 serverChannel.readable()
                 serverChannel.read()
-                let readCount = readCountHandler.readCount
+                let readCount = readCountHandler.value.readCount
                 // Directly trigger a read again without going through the pipeline. This will allow us to use serverChannel.readable()
                 serverChannel._channelCore.read0()
                 serverChannel.readable()
@@ -285,7 +310,7 @@ public final class AcceptBackoffHandlerTest: XCTestCase {
         XCTAssertEqual(
             0,
             try serverChannel.eventLoop.scheduleTask(in: .seconds(1)) {
-                readCountHandler.readCount
+                readCountHandler.value.readCount
             }.futureResult.wait()
         )
 
@@ -293,7 +318,7 @@ public final class AcceptBackoffHandlerTest: XCTestCase {
         XCTAssertEqual(
             1,
             try serverChannel.eventLoop.scheduleTask(in: .seconds(1)) {
-                readCountHandler.readCount
+                readCountHandler.value.readCount
             }.futureResult.wait()
         )
 
@@ -327,30 +352,32 @@ public final class AcceptBackoffHandlerTest: XCTestCase {
     }
 
     private func setupChannel(
-        group: EventLoopGroup,
-        readCountHandler: ReadCountHandler,
-        backoffProvider: @escaping (IOError) -> TimeAmount? = AcceptBackoffHandler.defaultBackoffProvider,
+        eventLoop: SelectableEventLoop,
+        readCountHandler: NIOLoopBound<ReadCountHandler>,
+        backoffProvider: @escaping @Sendable (IOError) -> TimeAmount? = AcceptBackoffHandlerTest.defaultBackoffProvider,
         errors: [Int32]
     ) throws -> ServerSocketChannel {
-        let eventLoop = group.next() as! SelectableEventLoop
         let socket = try NonAcceptingServerSocket(errors: errors)
         let serverChannel = try assertNoThrowWithValue(
             ServerSocketChannel(
                 serverSocket: socket,
                 eventLoop: eventLoop,
-                group: group
+                group: eventLoop
             )
         )
 
         XCTAssertNoThrow(try serverChannel.setOption(.autoRead, value: false).wait())
-        XCTAssertNoThrow(
-            try serverChannel.pipeline.addHandler(readCountHandler).flatMapThrowing { _ in
-                try serverChannel.pipeline.syncOperations.addHandler(
-                    AcceptBackoffHandler(backoffProvider: backoffProvider),
-                    name: self.acceptHandlerName
-                )
-            }.wait()
-        )
+
+        let configured = eventLoop.submit { [acceptHandlerName = self.acceptHandlerName] in
+            let sync = serverChannel.pipeline.syncOperations
+            try sync.addHandler(readCountHandler.value)
+            try sync.addHandler(
+                AcceptBackoffHandler(backoffProvider: backoffProvider),
+                name: acceptHandlerName
+            )
+        }
+
+        XCTAssertNoThrow(try configured.wait())
 
         XCTAssertNoThrow(
             try eventLoop.flatSubmit {