public EntityBuilder setContentType(final ContentType contentType) {
        this.contentType = contentType;
        return this;
    }
Sets the {@link ContentType} of the entity.

@param contentType the {@link ContentType} of the entity, may be null.
@return this instance.
httpclient5/src/main/java/org/apache/hc/client5/http/entity/EntityBuilder.java