HeadError

    pub const HeadError = error{
        /// Too many bytes of HTTP headers.
        ///
        /// The HTTP specification suggests to respond with a 431 status code
        /// before closing the connection.
        HttpHeadersOversize,
        /// Partial HTTP request was received but the connection was closed
        /// before fully receiving the headers.
        HttpRequestTruncated,
        /// The client sent 0 bytes of headers before closing the stream. This
        /// happens when a keep-alive connection is finally closed.
        HttpConnectionClosing,
        /// Transitive error occurred reading from `in`.
        ReadFailed,
    }