VB.NET IMAP BODY ENVELOPE separating to class - structure

Question

I would like separating the IMAP BODY ENVELOPE to own class.
(IMAP command: UID FETCH 4 (BODY ENVELOPE))
My class:
Class ENVELOPE
Class PL
Dim Name As String
Dim Value As String
End Class
Dim Type As String
Dim SubType As String
Dim PList() As PL 'Parameter list
Dim ID As String
Dim FileName As String 'Description
Dim Encoding As String
Dim Length As Integer
End Class
My IMAP result: https://pastebin.com/fv7yajsq
Try separating with:
Sub Separator(ByVal str As String)
Dim level As Integer = 0
Dim InAtt As String = ""
Dim lastl As Integer = 0
Dim skiplevel As Boolean = False
Dim levelss() As String = {0, 0, 0, 0, 0, 0}
For Each c As Char In str
If Not lastl = level Then
Debug.WriteLine(String.Join(",", levelss) & " - " & InAtt)
InAtt = ""
If lastl < level Then levelss(lastl) += 1
lastl = level
End If
If c = "("c And skiplevel = False Then
level += 1
ElseIf c = ")"c And skiplevel = False Then
levelss(level) = 0
level -= 1
ElseIf c = """" Then
skiplevel = Not skiplevel
InAtt &= c
Else
InAtt &= c
End If
Next
End Sub
Use Visual Basic 2015 with .NET 2.0 and IMAPv4
My question: How can separate IMAP result to my, or other class?