When writing request headers, use `header(name, value)` to set the only occurrence of `name` to `value`. If there are existing values, they will be removed before the new value is added. Use `addHeader(name, value)` to add a header without removing the headers already present.

    val hasRequestBody = HttpMethod.permitsRequestBody(request.method) && requestBody != null
    val isUpgradeRequest = "upgrade".equals(request.header("Connection"), ignoreCase = true)
    try {
      exchange.writeRequestHeaders(request)

      if (hasRequestBody) {
        // If there's a "Expect: 100-continue" header on the request, wait for a "HTTP/1.1 100
        // Continue" response before transmitting the request body. If we don't get that, return

    assertThat(connect.headers["Proxy-Connection"]).isEqualTo("Keep-Alive")
    assertThat(connect.headers["Host"]).isEqualTo("android.com:443")
    val get = server.takeRequest()
    assertThat(get.headers["Private"]).isEqualTo("Secret")
    assertThat(get.headers["User-Agent"]).isEqualTo("App 1.0")
    assertThat(hostnameVerifier.calls).containsExactly("verify android.com")
  }

  /**

 */
package okhttp3.internal.http1

import okhttp3.Headers
import okio.BufferedSource

/**
 * Parse all headers delimited by "\r\n" until an empty line. This throws if headers exceed 256 KiB.
 */
class HeadersReader(
  val source: BufferedSource,
) {
  private var headerLimit = HEADER_LIMIT.toLong()

  /** Read a single line counted against the header size limit. */
  fun readLine(): String {

      networkHeaders: Headers,
    ): Headers {
      val result = Headers.Builder()

      for (index in 0 until cachedHeaders.size) {
        val fieldName = cachedHeaders.name(index)
        val value = cachedHeaders.value(index)
        if ("Warning".equals(fieldName, ignoreCase = true) && value.startsWith("1")) {
          // Drop 100-level freshness warnings.
          continue
        }

// Index suggestions from existing Elasticsearch documents
DocumentReader reader = new ESSourceReader(
    client,
    suggester.settings(),
    "content-index",        // source index
    "document"             // document type
);

suggester.indexer()
    .indexFromDocument(reader, 2, 100)  // threads=2, batch=100
    .getResponse();
```

### Index from Query Logs

```java

      override fun matches(header: DerHeader): Boolean = true

      override fun fromDer(reader: DerReader): AnyValue {
        reader.read("ANY") { header ->
          val bytes = reader.readUnknown()
          return AnyValue(
            tagClass = header.tagClass,
            tag = header.tag,
            constructed = header.constructed,
            length = header.length,
            bytes = bytes,

describing the request at a high-level: _“fetch me this URL with these headers.”_ For correctness and efficiency, OkHttp rewrites your request before transmitting it.

OkHttp may add headers that are absent from the original request, including `Content-Length`, `Transfer-Encoding`, `User-Agent`, `Host`, `Connection`, and `Content-Type`. It will add an `Accept-Encoding` header for transparent response compression unless the header is already present. If you’ve got cookies, OkHttp will add a `Cookie`...

  return millis.toInt()
}

internal fun List<Header>.toHeaders(): Headers {
  val builder = Headers.Builder()
  for ((name, value) in this) {
    builder.addLenient(name.utf8(), value.utf8())
  }
  return builder.build()
}

internal fun Headers.toHeaderList(): List<Header> =
  (0 until size).map {
    Header(name(it), value(it))
  }

      // Parse each header.
      for (i in 0 until responseHeaders.size) {
        if (!responseHeaders.name(i).equals(HEADER_WEB_SOCKET_EXTENSION, ignoreCase = true)) {
          continue // Not a header we're interested in.
        }
        val header = responseHeaders.value(i)

        // Parse each extension.
        var pos = 0
        while (pos < header.length) {