@Override
    public Builder contract(final Contract contract) {
      checkNotNull(contract, "Argument contract must be not null");
      this.contract = new VertxDelegatingContract(contract);
      return this;
    }
Sets contract. Provided contract will be wrapped in {@link VertxDelegatingContract}.

@param contract contract
@return this builder
vertx/feign-vertx/src/main/java/feign/VertxFeign.java