v0.10.9

• Add rustls-tls-native-roots, rustls-tls-webpki-roots, and rustls-tls-manual-roots Cargo features, to configure which certificate roots to use with rustls.
• Add ClientBuilder::tcp_keepalive() method to enable TCP keepalive.
• Add ClientBuilder::http1_writev() method to force enable or disable vectored writes.
• Add Error::is_connect() method to identify if the error is related to connection-establishment.
• Add blocking::ClientBuilder::brotli() method.
• Windows: Update default protocol to HTTP for HTTPS system proxies, when a protocol is not specified.
• (wasm) Add support for Cloudflare workers runtime.
• (wasm) Add ClientBuilder::default_headers() method.
• (wasm) Add RequestBuilder::build() method.