func NewWriter(w io.Writer, h *sam.Header, wc int) (*Writer, error) {
	return NewWriterLevel(w, h, gzip.DefaultCompression, wc)
}
NewWriter returns a new Writer using the given SAM header. Write
concurrency is set to wc.
package bam
import (
	"bytes"
	"compress/gzip"
	"encoding/binary"
	"errors"
	"io"
	"github.com/biogo/hts/bgzf"
	"github.com/biogo/hts/sam"
)
type Writer struct {
	h *sam.Header
	bg  *bgzf.Writer
	buf bytes.Buffer
}