Android Question BLE Transmission of long packet has gaps, how to remove them?

Public Sub SendTxData(data() As Byte, dSize As Int)
    mDataToSend = data
    mDataSent = 0
    
    If dSize <= 20 Then
        'Send In one tranche
        Dim dataToSend(dSize) As Byte
    Else
        Dim dataToSend(20) As Byte
    End If
    
    Dim idx As Int
    For idx=0 To dataToSend.Length-1
        dataToSend(idx) = mDataToSend(idx)
    Next
    mDataSent = idx
    
    Try
        mManager.WriteData(mServiceId, mCharId, dataToSend)
    Catch
        Log("Attempted Write while disconnected")
        Log(LastException)
    End Try
End Sub
#If B4A
Private Sub mManager_WriteComplete (Characteristic As String, Status As Int)
#Else If B4I
Private Sub mManager_WriteComplete (Characteristic As String, Success As Boolean)
#End If
    If mDataSent < mDataToSend.Length Then
        'More Data To Send
        Dim remaining As Int = mDataToSend.Length - mDataSent
        
        If remaining <= 20 Then
            'Send In one tranche
            Dim dataToSend(remaining) As Byte
        Else
            Dim dataToSend(20) As Byte
        End If
    
        Dim idx As Int
        For idx=0 To dataToSend.Length-1
            dataToSend(idx) = mDataToSend(mDataSent + idx)
        Next
        mDataSent = mDataSent + idx
    
        Try
            mManager.WriteData(mServiceId, mCharId, dataToSend)
        Catch
            Log("Attempted Write while disconnected")
            Log(LastException)
        End Try
    Else
        'Finished Writing
        mTmrRxTimeout.Enabled = True
    End If
End Sub