AK: Use size_t for ByteBuffer sizes

This matches what we already do for string types.

Libraries/LibCore/EventLoop.cpp

@@ -90,7 +90,7 @@ public:
         s_rpc_clients.set(m_client_id, this);
         add_child(*m_socket);
         m_socket->on_ready_to_read = [this] {
-            i32 length;
+            u32 length;
             int nread = m_socket->read((u8*)&length, sizeof(length));
             if (nread == 0) {
                 dbg() << "RPC client disconnected";
@@ -117,7 +117,7 @@ public:
     void send_response(const JsonObject& response)
     {
         auto serialized = response.to_string();
-        i32 length = serialized.length();
+        u32 length = serialized.length();
         m_socket->write((const u8*)&length, sizeof(length));
         m_socket->write(serialized);
     }

Libraries/LibCore/Gzip.cpp

@@ -40,7 +40,7 @@ bool CGzip::is_compressed(const ByteBuffer& data)
 // see: https://tools.ietf.org/html/rfc1952#page-5
 static Optional<ByteBuffer> get_gzip_payload(const ByteBuffer& data)
 {
-    int current = 0;
+    size_t current = 0;
     auto read_byte = [&]() {
         if (current >= data.size()) {
             ASSERT_NOT_REACHED();

Libraries/LibCore/HttpRequest.cpp

@@ -82,7 +82,7 @@ Optional<HttpRequest> HttpRequest::from_raw_request(const ByteBuffer& raw_reques
     };
 
     State state { State::InMethod };
-    int index = 0;
+    size_t index = 0;
 
     auto peek = [&](int offset = 0) -> u8 {
         if (index + offset >= raw_request.size())

Libraries/LibCore/Socket.cpp

@@ -162,12 +162,12 @@ ByteBuffer Socket::receive(int max_size)
 
 bool Socket::send(const ByteBuffer& data)
 {
-    int nsent = ::send(fd(), data.data(), data.size(), 0);
+    ssize_t nsent = ::send(fd(), data.data(), data.size(), 0);
     if (nsent < 0) {
         set_error(errno);
         return false;
     }
-    ASSERT(nsent == data.size());
+    ASSERT(static_cast<size_t>(nsent) == data.size());
     return true;
 }