<PackageReference Include="NETStandard.Library" Version="2.0.3" />

System.Net.Mail.AttachmentBase

public abstract class AttachmentBase : IDisposable
namespace System.Net.Mail { public abstract class AttachmentBase : IDisposable { public string ContentId { get; set; } public Stream ContentStream { get; } public ContentType ContentType { get; set; } public TransferEncoding TransferEncoding { get; set; } protected AttachmentBase(Stream contentStream); protected AttachmentBase(Stream contentStream, ContentType contentType); protected AttachmentBase(Stream contentStream, string mediaType); protected AttachmentBase(string fileName); protected AttachmentBase(string fileName, ContentType contentType); protected AttachmentBase(string fileName, string mediaType); public void Dispose(); protected virtual void Dispose(bool disposing); } }