function _Requestor(sServiceUrl, mHeaders, mQueryParams, oModelInterface, bWithCredentials) {
		this.mBatchQueue = {};
		this.bBatchSent = false;
		this.mHeaders = mHeaders || {};
		this.aLockedGroupLocks = [];
		this.oModelInterface = oModelInterface;
		this.oOptimisticBatch = null; // optimistic batch processing off
		this.sQueryParams = _Helper.buildQuery(mQueryParams); // Used for $batch and CSRF token only
		this.mRunningChangeRequests = {}; // map from group ID to a SyncPromise[]
		this.iSessionTimer = 0;
		this.iSerialNumber = 0;
		this.sServiceUrl = sServiceUrl;
		this.vStatistics = mQueryParams && mQueryParams["sap-statistics"];
		this.bWithCredentials = bWithCredentials;
		this.processSecurityTokenHandlers(); // sets this.oSecurityTokenPromise
	}
Constructor for a new <code>_Requestor</code> instance for the given service URL and default
headers.

@param {string} sServiceUrl
  URL of the service document to request the CSRF token from; also used to resolve
  relative resource paths (see {@link #request})
@param {object} [mHeaders={}]
  Map of default headers; may be overridden with request-specific headers; certain
  predefined OData V4 headers are added by default, but may be overridden
@param {object} [mQueryParams={}]
  A map of query parameters as described in
  {@link sap.ui.model.odata.v4.lib._Helper.buildQuery}; used only to request the CSRF token
@param {object} oModelInterface
  An interface allowing to call back to the owning model (see {@link .create})
@param {boolean} [bWithCredentials]
  Whether the XHR should be called with <code>withCredentials</code>

@alias sap.ui.model.odata.v4.lib._Requestor
@constructor
@private