Function decode 

pub(super) const fn decode<'a, P: PropertyConstraint>(
    r: &mut Reader<'a>,
) -> Result<(PacketId, &'a Properties<P>, &'a [u8]), DecodeError>

Decodes a “packet id + properties + payload” body from the reader.

The remaining bytes after the properties become the payload; an empty payload is rejected, since every packet using this shape carries at least one entry.

Errors

Returns DecodeError if the data is malformed, the packet id is zero, or the properties contain disallowed ids.