code: public static ReadOnlyHttp2Headers clientHeaders(boolean validateHeaders,
                                                       AsciiString method, AsciiString path,
                                                       AsciiString scheme, AsciiString authority,
                                                       AsciiString... otherHeaders) {
          return new ReadOnlyHttp2Headers(validateHeaders,
                  new AsciiString[] {
                    PseudoHeaderName.METHOD.value(), method, PseudoHeaderName.PATH.value(), path,
                    PseudoHeaderName.SCHEME.value(), scheme, PseudoHeaderName.AUTHORITY.value(), authority
                  },
                  otherHeaders);
      }
docs: Create a new read only representation of headers used by clients.
  @param validateHeaders {@code true} will run validation on each header name/value pair to ensure protocol
  compliance.
  @param method The value for {@link PseudoHeaderName#METHOD}.
  @param path The value for {@link PseudoHeaderName#PATH}.
  @param scheme The value for {@link PseudoHeaderName#SCHEME}.
  @param authority The value for {@link PseudoHeaderName#AUTHORITY}.
  @param otherHeaders A an array of key:value pairs. Must not contain any
  <a href="https://tools.ietf.org/html/rfc7540#section-8.1.2.1">pseudo headers</a>
  or {@code null} names/values.
  A copy will <strong>NOT</strong> be made of this array. If the contents of this array
  may be modified externally you are responsible for passing in a copy.
  @return a new read only representation of headers used by clients.