if f, err := os.Open(sessionPolicyFile); err != nil {
			log.Fatalf("Unable to open session policy file: %v", err)
		} else {
			defer f.Close()
			bs, err := io.ReadAll(f)
			if err != nil {
				log.Fatalf("Error reading session policy file: %v", err)
			}
			policy = string(bs)
		}
		stsOpts.Policy = policy
	}
	if expiryDuration != 0 {
		stsOpts.DurationSeconds = int(expiryDuration.Seconds())
	}

		if f, err := os.Open(sessionPolicyFile); err != nil {
			log.Fatalf("Unable to open session policy file %s: %v", sessionPolicyFile, err)
		} else {
			bs, err := io.ReadAll(f)
			if err != nil {
				log.Fatalf("Error reading session policy file: %v", err)
			}
			policy = string(bs)
		}
		ldapOpts = append(ldapOpts, cr.LDAPIdentityPolicyOpt(policy))
	}
	if expiryDuration != 0 {

// simultaneously, but each returned writer will be used only by
// one goroutine at a time.
type Compressor func(w io.Writer) (io.WriteCloser, error)

// A Decompressor returns a new decompressing reader, reading from r.
// The [io.ReadCloser]'s Close method must be used to release associated resources.
// The Decompressor itself must be safe to invoke from multiple goroutines
// simultaneously, but each returned reader will be used only by

			//    https://blog.cloudflare.com/when-tcp-sockets-refuse-to-die/
			// This is a sensitive configuration, it is better to set it to high values, > 60 secs since it can
			// affect clients reading data with a very slow pace  (disappropriate with socket buffer sizes)
			if opts.UserTimeout > 0 {
				_ = syscall.SetsockoptInt(fd, syscall.IPPROTO_TCP, unix.TCP_USER_TIMEOUT, opts.UserTimeout)
			}

	jsonfmt "github.com/minio/minio/internal/s3select/json"
	"github.com/minio/minio/internal/s3select/jstream"
	"github.com/minio/minio/internal/s3select/sql"
)

// Reader implements reading records from parquet input.
type Reader struct {
	io.Closer
	r *parquetgo.FileReader
}

// NewParquetReader creates a Reader2 from a io.ReadSeekCloser.

	Start *uint64 `xml:"Start"`
	// End is the offset of the last byte that should be returned when Start
	// is set, otherwise it is the offset from EOF to start reading.
	End *uint64 `xml:"End"`
}

// Validate if the scan range is valid.
func (s *ScanRange) Validate() error {
	if s == nil {
		return nil
	}
	if s.Start == nil && s.End == nil {

	stats, err := readStat(statsFile)
	if err != nil {
		return IOStats{}, err
	}
	if len(stats) < 11 {
		return IOStats{}, fmt.Errorf("found invalid format while reading %v", statsFile)
	}
	// refer https://www.kernel.org/doc/Documentation/block/stat.txt
	iostats = IOStats{
		ReadIOs:      stats[0],
		ReadMerges:   stats[1],
		ReadSectors:  stats[2],
		ReadTicks:    stats[3],

	Val string
}

// ObjectVersion object version key/versionId
type ObjectVersion struct {
	ObjectName string
	VersionID  string `json:"VersionId,omitempty"`
}

// ReqInfo stores the request info.
// Reading/writing directly to struct requires appropriate R/W lock.
type ReqInfo struct {
	RemoteHost   string           // Client Host/IP
	Host         string           // Node Host/IP
	UserAgent    string           // User Agent

				ExpectedMD5:   v.Expected.String(),
				CalculatedMD5: v.Computed.String(),
			}
		}
	}
	return n, err
}

// Size returns the absolute number of bytes the Reader
// will return during reading. It returns -1 for unlimited
// data.
func (r *Reader) Size() int64 { return r.size }

// ActualSize returns the pre-modified size of the object.
// DecompressedSize - For compressed objects.

The **Advanced User Guide** builds on this one, uses the same concepts, and teaches you some extra features.

But you should first read the **Tutorial - User Guide** (what you are reading right now).