diff --git a/Sources/StatsdClient/StatsdClient.swift b/Sources/StatsdClient/StatsdClient.swift
index 2508ac8..9730f2f 100644
--- a/Sources/StatsdClient/StatsdClient.swift
+++ b/Sources/StatsdClient/StatsdClient.swift
@@ -447,7 +447,7 @@ private final class Client: @unchecked Sendable {
         return bootstrap.bind(host: self.address.protocol == .inet6 ? "::" : "0.0.0.0", port: 0)
     }
 
-    private final class Encoder: ChannelOutboundHandler {
+    private final class Encoder: ChannelOutboundHandler, Sendable {
         public typealias OutboundIn = Metric
         public typealias OutboundOut = AddressedEnvelope<ByteBuffer>
 
diff --git a/Tests/StatsdClientTests/TestServer.swift b/Tests/StatsdClientTests/TestServer.swift
index e06ebb2..1650b91 100644
--- a/Tests/StatsdClientTests/TestServer.swift
+++ b/Tests/StatsdClientTests/TestServer.swift
@@ -36,7 +36,9 @@ final class TestServer: @unchecked Sendable {
     func connect() -> EventLoopFuture<Void> {
         let bootstrap = DatagramBootstrap(group: self.eventLoopGroup)
             .channelOption(ChannelOptions.socket(SocketOptionLevel(SOL_SOCKET), SO_REUSEADDR), value: 1)
-            .channelInitializer { channel in channel.pipeline.addHandler(Aggregator(delegate: self.store)) }
+            .channelInitializer { channel in
+                channel.pipeline.addHandler(Aggregator(delegate: { self.store(address: $0, value: $1) }))
+            }
 
         return bootstrap.bind(host: self.host, port: self.port).map { _ in () }
     }
@@ -57,12 +59,12 @@ final class TestServer: @unchecked Sendable {
         }
     }
 
-    class Aggregator: ChannelInboundHandler {
+    final class Aggregator: ChannelInboundHandler, Sendable {
         typealias InboundIn = AddressedEnvelope<ByteBuffer>
 
-        let delegate: (SocketAddress, String) -> Void
+        let delegate: @Sendable (SocketAddress, String) -> Void
 
-        init(delegate: @escaping (SocketAddress, String) -> Void) {
+        init(delegate: @escaping @Sendable (SocketAddress, String) -> Void) {
             self.delegate = delegate
         }