Use ValueTasks instead of Tasks

[HarryCordewener]

https://devblogs.microsoft.com/dotnet/understanding-the-whys-whats-and-whens-of-valuetask/

This is a Binary-Breaking change, and will require the Extensions to get a similar update and refer explicitly to this version and above.

[Lozko1991]

Does it make sense to have ALL methods return ValueTask in our API?
I have checked this code and cant understand why we have ValueTask there

public async ValueTask<T> SendAsync<T>(HttpMethod m, string url, object body = null,
    string transaction = null, bool throwOnError = true, bool auth = true,
    IDictionary<string, string> headers = null,
    CancellationToken cancellationToken = default)
{
    await Authenticate(auth, cancellationToken).ConfigureAwait(false); // this method has sync way, its ok

    var msg = new HttpRequestMessage(m, _configuration.Server + url);
    ApplyHeaders(transaction, auth, msg, headers);

    if (body != null)
    {
        var json = _configuration.Serializer.Serialize(body);
        msg.Content = new StringContent(json, Encoding.UTF8,
            "application/json");
    }
    else
    {
        msg.Headers.Add(HttpRequestHeader.ContentLength.ToString(), "0");
    }

    // but here we always have the really asyn call
    var res = await _httpClient.SendAsync(msg, cancellationToken).ConfigureAwait(false); 

    if (!res.IsSuccessStatusCode)
        if (throwOnError)
        {
            var errorContent = await res.Content.ReadAsStringAsync().ConfigureAwait(false);
            var error = _configuration.Serializer.Deserialize<ErrorResponse>(errorContent);
            throw new ArangoException(errorContent, error.ErrorMessage,
                (HttpStatusCode) error.Code, (ArangoErrorCode) error.ErrorNum);
        }
        else
        {
            return default;
        }

    var content = await res.Content.ReadAsStringAsync().ConfigureAwait(false);

    if (res.Headers.Contains("X-Arango-Error-Codes"))
    {
        var errors = _configuration.Serializer.Deserialize<IEnumerable<ErrorResponse>>(content)
            .Select(error => new ArangoError(error.ErrorMessage, (ArangoErrorCode) error.ErrorNum));
        throw new ArangoException(content, errors);
    }

    if (content == "{}" || string.IsNullOrWhiteSpace(content))
        return default;

    return _configuration.Serializer.Deserialize<T>(content);
}

await Authenticate(auth, cancellationToken).ConfigureAwait(false); // this method has sync way, its ok

// but here we always have the really asyn call
var res = await _httpClient.SendAsync(msg, cancellationToken).ConfigureAwait(false);

So, would it be better to leave high-level API with Tasks, and use ValueTasks only in places, where exist ways to run synchronously?