ABNF.atext Field

[This is preliminary documentation and subject to change.]

RFC 2822 Section 3.2.4

public const string atext = "A-Za-z0-9\x21\x23-\x27\x2A\x2B\x2D\x2F\x3D\x3F\x5E\x5F\x60\x7B-\x7E";