### HTTP Client Architecture

```
SwitchableHttpClient (extends FaultTolerantClient)
    ├── Hc5HttpClient (default) - Apache HttpComponents 5.x
    └── Hc4HttpClient (fallback) - Apache HttpComponents 4.x

HcHttpClient (abstract base class)
    ├── Hc4HttpClient
    └── Hc5HttpClient
```

Switch via system property: `-Dfess.crawler.http.client=hc4` or `hc5` (default)

		<dependency>
			<groupId>org.apache.httpcomponents</groupId>
			<artifactId>httpcore</artifactId>
			<version>${httpcomponents.core.version}</version>
		</dependency>
		<dependency>
			<groupId>org.apache.httpcomponents</groupId>
			<artifactId>httpclient</artifactId>
			<version>${httpcomponents.version}</version>
		</dependency>
		<dependency>
			<groupId>org.apache.httpcomponents</groupId>

					<groupId>org.codehaus.groovy</groupId>
					<artifactId>groovy</artifactId>
				</exclusion>
				<exclusion>
					<groupId>org.apache.httpcomponents</groupId>
					<artifactId>httpclient</artifactId>
				</exclusion>
				<exclusion>
					<groupId>org.apache.httpcomponents</groupId>
					<artifactId>httpcore</artifactId>
				</exclusion>
				<exclusion>
					<groupId>org.opensearch.plugin</groupId>

hamcrest-library = { module = "org.hamcrest:hamcrest-library", version.ref = "hamcrest-library" }
guava-jre = { module = "com.google.guava:guava", version.ref = "guava" }
http-client5 = { module = "org.apache.httpcomponents.client5:httpclient5", version.ref = "http-client5" }
jetty-client = { module = "org.eclipse.jetty:jetty-client", version.ref = "jetty-client" }