# Omgevingsvariabelen

/// tip

Als je al weet wat "omgevingsvariabelen" zijn en hoe je ze kunt gebruiken, kun je deze stap gerust overslaan.

///

Een omgevingsvariabele (ook bekend als "**env var**") is een variabele die **buiten** de Python-code leeft, in het **besturingssysteem** en die door je Python-code (of door andere programma's) kan worden gelezen.

): String? = headers[name] ?: defaultValue

@Throws(IOException::class)
fun Response.commonPeekBody(byteCount: Long): ResponseBody {
  val peeked = body.source().peek()
  val buffer = Buffer()
  peeked.request(byteCount)
  buffer.write(peeked, minOf(byteCount, peeked.buffer.size))
  return buffer.asResponseBody(body.contentType(), buffer.size)
}

fun Response.commonNewBuilder(): Response.Builder = Response.Builder(this)

    while (true) {
      if (peek == null) {
        peek = readToken()
        if (skipCommasAndWhitespace()) break // We peeked a scheme name followed by ','.
        eqCount = skipAll('='.code.toByte())
      }
      if (eqCount == 0) break // We peeked a scheme name.
      if (eqCount > 1) return // Unexpected '=' characters.
      if (skipCommasAndWhitespace()) return // Unexpected ','.

		if offset < 0 {
			return 0, errors.New("Invalid offset")
		}
		d.idx = offset
	case io.SeekCurrent:
		if d.idx+offset < 0 {
			return 0, errors.New("Invalid offset")
		}
		d.idx += offset
	case io.SeekEnd:
		if d.length+offset < 0 {
			return 0, errors.New("Invalid offset")
		}
		d.idx = d.length + offset
	}
	return d.idx, nil
}

func TestDummyDataGenerator(t *testing.T) {

func (r *Reader) Seek(offset int64, whence int) (int64, error) {
	r.prevRune = -1
	var abs int64
	switch whence {
	case io.SeekStart:
		abs = offset
	case io.SeekCurrent:
		abs = r.i + offset
	case io.SeekEnd:
		abs = int64(len(r.s)) + offset
	default:
		return 0, errors.New("bytes.Reader.Seek: invalid whence")
	}
	if abs < 0 {
		return 0, errors.New("bytes.Reader.Seek: negative position")
	}
	r.i = abs

		{seek: io.SeekCurrent, off: 1, wantpos: 1<<33 + 1, readerr: io.EOF},
		{seek: io.SeekStart, n: 5, want: "01234"},
		{seek: io.SeekCurrent, n: 5, want: "56789"},
		{seek: io.SeekEnd, off: -1, n: 1, wantpos: 9, want: "9"},
	}

	for i, tt := range tests {
		pos, err := r.Seek(tt.off, tt.seek)
		if err == nil && tt.seekerr != "" {
			t.Errorf("%d. want seek error %q", i, tt.seekerr)
			continue

  /**
   * Returns a value from this adapter.
   *
   * This must always return a value, though it doesn't necessarily need to consume data from
   * [reader]. For example, if the reader's peeked tag isn't readable by this adapter, it may return
   * a default value.
   *
   * If this does read a value, it starts with the tag and length, and reads an entire value,
   * including any potential composed values.
   *