NewWriter returns a new multipart Writer with a random boundary, writing to w.

ContentTransferEncoding7Bit is the 7bit encoding.

ContentTransferEncoding8Bit is the 8bit encoding.

ContentTransferEncodingBase64 is the base64 encoding.

ContentTransferEncodingBinary is the binary encoding.

ContentTransferEncoding7Bit is the 7bit encoding.

ContentTransferEncodingQuotedPrintable is the quoted-printable encoding.

A Writer generates multipart messages.